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Sample records for prolonged ozone exposure

  1. Selective enhancement of xenobiotic metabolizing systems of rat lungs by prolonged exposure to ozone

    SciTech Connect

    Takahashi, Y.; Miura, T.

    1987-04-01

    Male Wistar rats were exposed to 0.2 and 0.4 ppm O/sub 3/ for 4, 8, and 12 weeks and to 0.1 and 0.2 ppm O/sub 3/ for 4 weeks to examine the effects of prolonged exposure to O/sub 3/ on the xenobiotic metabolizing systems in the lung. Exposures to 0.2 and 0.4 ppm O/sub 3/ caused a significant increase in the NADPH-cytochrome P-450 reductase activity and cytochrome P-450 content in a dose-dependent manner during 4-12 weeks, whereas NADH-cytochrome b5 reductase was not altered. After 12 weeks of exposure to 0.4 ppm O/sub 3/, NADPH-cytochrome P-450 reductase and cytochrome P-450 reached a maximum showing 138 and 221% those of the control levels, respectively. At 0.1 ppm O/sub 3/, the cytochrome P-450 content still increased significantly to 152% that of the control on the fourth week. In parallel to the increment of cytochrome P-450 benzo(a)pyrene hydroxylase and 7-ethoxycoumarin O-deethylase increased significantly during 4-12 weeks of exposures to 0.2 and 0.4 ppm O/sub 3/. After a 4-week exposure to 0.1 and 0.2 ppm O/sub 3/, benzphetamine N-demethylase increased to the largest degree among the enzymes metabolizing four kinds of xenobiotics examined. 7-Ethoxycoumarin O-deethylase also increased significantly but of smaller magnitude, whereas coumarin hydroxylase was not affected. These results show that prolonged exposures to 0.1-0.4 ppm O/sub 3/ persistently enhance pulmonary cytochrome P-450 systems. It is also suggested that some isozyme(s) of pulmonary cytochrome P-450, especially that catalyzing benzphetamine N-demethylation, are preferentially increased by exposure to low levels of O/sub 3/.

  2. Responses of older men with and without chronic obstructive pulmonary disease to prolonged ozone exposure

    SciTech Connect

    Gong, H. Jr.; Shamoo, D.A.; Anderson, K.R.; Linn, W.S.

    1997-01-01

    We tested responses to ozone (O{sub 3}) under simulated {open_quotes}worst-case{close_quotes} ambient exposure conditions. Subjects included 9 men who had severe chronic obstructive pulmonary disease (COPD) with subnormal carbon monoxide diffusing capacity (i.e., an emphysemic component) and 10 age-matched healthy men. Each subject was exposed to 0.24 ppm O{sub 3} and to clean air (control) in an environmentally controlled chamber at 24{degrees}C and 40% relative humidity. Exposures were randomized, they occurred 1 wk apart, and they lasted 4 h. During each half-hour interval, light exercise occurred (e.e., average ventilation 20 l/mm) for 15 min. during both control and O{sub 3} exposures, group mean symptom intensity and specific airway resistance (SRaw) increased, whereas forced expiratory performance decreased. The healthy subgroup`s mean arterial oxygen saturation (SaO{sub 2}) rose slightly, and the COPD subgroup`s mean SaO{sub 2} declined slightly, during exercise. Group mean forced expiratory volume in 1 s (FEV{sub 1.0}) declined significantly in O{sub 3} exposures, compared with controls (p {approx}.01). Mean excess FEV{sub 1.0} loss after 4 h in O{sub 3} (relative to control) was 8% of the preexposure value in the COPD subgroup, compared with 3% in the healthy subgroup (p > .05 [nonsignificant]). Overall FEV{sub 1.0} loss during O{sub 3} exposures, including exercise effects, averaged 19% in the COPD subgroup, compared with 2% in the healthy subgroup (p < .001). Symptoms, SRaw, and SaO{sub 2} responses, as well as healthy subjects` postexposure bronchial reactivity, differed little between O{sub 3}-exposed and control subjects. We therefore concluded that in older men with or without severe COPD, O{sub 3} causes lung dysfunction under {open_quotes}worst-case{close_quotes} ambient exposure conditions, despite older subjects` comparative unresponsiveness to O{sub 3}. 30 refs., 2 figs., 2 tabs.

  3. Changes in pulmonary function and airway reactivity due to prolonged exposure to typical ambient ozone (O/sub 3/) levels

    SciTech Connect

    Horstman, D.; McConnell, W.; Folinsbee, L.; Abdul-Salaam, S.; Ives, P.

    1988-05-01

    Daily ambient ozone levels between 0.08 and 0.12 ppm for periods exceeding 6 hours often occur in many urban, suburban, and rural areas of the United States and Europe. Substantial decrements in pulmonary functions, moderate to severe respiratory symptoms, and increased airway reactivity have been observed in young men performing moderate to heavy exercise. This study evaluates pulmonary responses of 22 healthy nonsmoking males, resulting from exposures to 0.08, 0.10, and 0.12 ppm ozone.

  4. Prolonged exposure to low doses of ozone: short- and long-term changes in behavioral performance in mice.

    PubMed

    Sorace, A; de Acetis, L; Alleva, E; Santucci, D

    2001-02-01

    Two separate experiments were designed to assess the effects of ozone exposure on outbred CD-1 mice. In the first experiment, adult males were exposed continuously to O3 at 0, 0.3, or 0.6 ppm for 30 days and their behavior was assessed in a 5-min open-field test on exposure days 4 and 19 and on day 3 after the end of the exposure phase. In addition, mice performed a Morris water maze task from exposure day 24 to 28. In the second experiment, adult females were exposed from 30 days prior to the formation of breeding pairs until gestational day 17 to the same doses used in the first experiment. Litters were fostered at birth to untreated dams and neurobehavioral development of the offspring was investigated until adulthood. Specifically, somatic and sensorimotor development [postnatal day (PND) 2-20], homing performance (PND 12), motor activity (PND 21), passive avoidance (PND 22-23), water maze performances (PND 70-74), and response to a nociceptive stimulus (PND 100) were assessed. Results from both experiments confirm that exposure to O3 slightly but selectively affected neurobehavioral performance in rodents. Exposure to O3 did not grossly affect neurobehavioral development, whereas it consistently impaired reversal learning in the Morris water maze test in both prenatally and adult exposed mice. Moreover, longer latency to step-through in the first trial of the passive avoidance test and a decrease in wall rearing in the hot-plate test were recorded in O3 prenatally exposed mice. Except for the first open-field test, altered responses were observed only in animals exposed at the intermediate concentration of the gas. Adaptation and/or onset of compensatory mechanisms might be responsible for the lack of linear dose-response relationships.

  5. Changes in pulmonary function and airway reactivity due to prolonged exposure to typical ambient ozone (O sub 3 ) levels

    SciTech Connect

    Horstman, D.; McDonnell, W.; Folinsbee, L.; Abdul-Salaam, S.; Ives, P.

    1989-01-01

    Previously observed (JAPCA 38:28-35, 1988) pulmonary responses of delta FEV1 (-13%), moderate to severe pain upon inspiration, and a doubling of PD100 for methacholine following prolonged moderate exercise at 0.12 ppm O3 were of sufficient magnitude to warrant the assessing of responses at a lower range of concentrations, i.e., 0.08, 0.10 and 0.12 ppm O3. Exposures consisted of six 50-min exercises (VE approximately equals 40 L/min), each followed by 10-min rest; a 35-min lunch break was included. When compared with exposures to 0.00 ppm, substantial pulmonary function decrements, respiratory symptoms and increases in nonspecific airway reactivity were observed at all three O3 concentrations. For example, decreases in FEV1 (P < 0.01) of 7%, 7% and 12% were observed at 0.08, 0.10 and 0.12 ppm O3, respectively. The ratios (P < 0.005) of PD100 observed in 0.00 ppm to that in O3 were 1.56 at 0.08 ppm, 1.89 at 0.10 ppm, and 2.21 at 0.12 ppm O3. It is concluded that exercise representative of a day of moderate to heavy work or play performed during exposures to O3 at levels and pattern often found in ambient air induced clinically meaningful pulmonary responses.

  6. [Ozone exposure and asthma].

    PubMed

    Kleis, S; Louis, R; Bartsch, P

    2003-03-01

    Ozone is a pollutant the production of which depends on weather conditions and car engine combustion. Numerous epidemiological studies have indicated that high ozone levels correlated with morbidity in asthma. Experimental studies have shown that exposure of healthy subjects and asthmatics to ozone levels comparable to those measured in ambient air during hot summer days can generate respiratory symptoms, neutrophilic airways inflammation and lung function impairment. Lung function changes following ozone exposure are more pronounced in asthmatics and are dependent on the duration and intensity of exposure, a previous exposure and the nutritional status of the subjects. The airway epithelial cell layer is likely to play a pivotal role in initiating the inflammatory process following ozone exposure. Control of ambient air ozone levels must be a target for public health authorities.

  7. Effects of prolonged, sequential exposure to acid fog and ozone on pulmonary function in exercising, normal subjects. Final report, 28 Feb 89-28 Dec 90

    SciTech Connect

    Balmes, J.

    1990-05-01

    Thirty-nine apparently healthy and asymptomatic subjects were selected for a study that screened for sensitivity to ozone. After three hours of ozone exposure (at 0.20 ppm), eighteen of the subjects (46 percent) experienced a 10 percent reduction in forced expiratory volume, an indicator of exhaling ability. After four hours of exposure, 62 percent of the subjects experienced a similar reduction in expiratory volume. Further, narrowing of airways among the sensitive subjects was suggested by results of the methacholine challenge test, a standard test for measuring airway resistance. The lung capacity of all subjects decreased progressively during ozone exposures. Capacity was unchanged during acidic fog and pollutant-free air exposures. No statistically significant differences in airway resistance, airway responsiveness and symptoms that could be attributed to acid fog exposure were observed. The study indicates that exposue to fog containing nitric acid followed by exposure to ozone does not have additive or synergistic acute effects. However, the study confirms earlier indications that many apparently healthy and asymptomatic individuals are susceptible to and adversely affected by ozone at relatively low concentrations.

  8. Ozone exposure of a weed community produces adaptive changes in seed populations of Spergula arvensis.

    PubMed

    Landesmann, Jennifer B; Gundel, Pedro E; Martínez-Ghersa, M Alejandra; Ghersa, Claudio M

    2013-01-01

    Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production.

  9. Ozone Exposure of a Weed Community Produces Adaptive Changes in Seed Populations of Spergula arvensis

    PubMed Central

    Landesmann, Jennifer B.; Gundel, Pedro E.; Martínez-Ghersa, M. Alejandra; Ghersa, Claudio M.

    2013-01-01

    Tropospheric ozone is one of the major drivers of global change. This stress factor alters plant growth and development. Ozone could act as a selection pressure on species communities composition, but also on population genetic background, thus affecting life history traits. Our objective was to evaluate the consequences of prolonged ozone exposure of a weed community on phenotypic traits of Spergulaarvensis linked to persistence. Specifically, we predicted that the selection pressure exerted by high ozone concentrations as well as the concomitant changes in the weed community would drive population adaptive changes which will be reflected on seed germination, dormancy and longevity. In order to test seed viability and dormancy level, we conducted germination experiments for which we used seeds produced by S. arvensis plants grown within a weed community exposed to three ozone treatments during four years (0, 90 and 120 ppb). We also performed a soil seed bank experiment to test seed longevity with seeds coming from both the four-year ozone exposure experiment and from a short-term treatment conducted at ambient and added ozone concentrations. We found that prolonged ozone exposure produced changes in seed germination, dormancy and longevity, resulting in three S. arvensis populations. Seeds from the 90 ppb ozone selection treatment had the highest level of germination when stored at 75% RH and 25 °C and then scarified. These seeds showed the lowest dormancy level when being subjected to 5 ºC/5% RH and 25 ºC/75% followed by 5% RH storage conditions. Furthermore, ozone exposure increased seed persistence in the soil through a maternal effect. Given that tropospheric ozone is an important pollutant in rural areas, changes in seed traits due to ozone exposure could increase weed persistence in fields, thus affecting weed-crop interactions, which could ultimately reduce crop production. PMID:24086640

  10. Iron decreases biological effects of ozone exposure

    EPA Science Inventory

    CONTEXT: Ozone (0(3)) exposure is associated with a disruption of iron homeostasis and increased availability of this metal which potentially contributes to an oxidative stress and biologicaleffects. OBJECTIVE: We tested the postulate that increased concentrations of iron in c...

  11. [Aircraft cabin air quality: exposure to ozone].

    PubMed

    Uva, António De Sousa

    2002-01-01

    Ozone is the principal component involved in photochemical pollution of the air. As an irritant of the respiratory system, its effects on the health of those exposed to it are characterised essentially by coughing, shortness of breath, chest pain or tightness and alterations to the pulmonary mechanical function. Additionally, a higher frequency and severity of asthmatic exacerbation and the occurrence of eye irritation are linked to environmental exposure to O3. In the early 1960s the first studies on the exposure to O3 in aircraft cabins appeared, prompted by the occurrence of clinical complaints of irritation of the respiratory tract in crewmembers and passengers. The symptoms had hitherto been attributed to the action of other factors, such as the ventilation system and low level of humidity in the air. An updating is done by author of some factors related to the quality of air inside aircraft cabins, namely the exposure to ozone in crewmembers and passengers.

  12. AN HISTORICAL OVERVIEW OF THE OZONE EXPOSURE PROBLEM

    EPA Science Inventory

    Ozone can be found in essentially all locations in the troposphere. Too much exposure of vegetation and humans to this potent oxidizing gas can prove toxic. Reports of human toxicity to ozone first appeared in the 1800's from accidental occupational exposures when ozone was fir...

  13. Ecosystem Consequences of Prolonged Ozone Pollution in the Southern Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Cousins, S.; Battles, J. J.; Cisneros, R.; Esperanza, A.; Swenson, D.

    2015-12-01

    While acute O3 exposure is widely known to damage plant tissues, the chronic effects on long lived organisms such as trees remain unclear. In the southern Sierra Nevada, O3 pollution has afflicted pine-dominated forests for over 40 years. Here we report the results of a long-term study of O3 impact on tree injury, growth, and mortality. Our study employed a network of forest plots along a gradient of O3 pollution with recurring measurements from 1991-2012. Over the same period and locations, summer O3 was monitored via partnership with USNPS and USFS, making this one of the longest known ecosystem studies of O3 pollution and its effects. We found that exposure at the most polluted sites declined 33%, from a W126 index of 20.12 ppm-hrs in 1992 to 13.5 ppm-hrs in 2012. The severity of foliar pollution damage at these sites also declined, from 43.9 on the 0-100 Ozone Injury Index (OII) scale to 34.2, a drop of 22%. At locations with lower O3 exposure, damage declined from OII of 16.9 to 9.2. Mean annual tree mortality rates over the 20 year period, calculated with a profile likelihood approach, were 0.5%/yr (95% CI 0.3 to 0.8 %/yr). This rate is similar to that of healthy canopy trees in similar unpolluted stands. However, low and declining tree growth rates reveal possible ecosystem impacts of prolonged exposure to pollution. Across affected sites, mean relative growth rates were 1.1%/yr in 1991-2000, and just 0.9%/yr in 2000-2011, a decline of 15.6% in the second decade. Initial analyses suggest that tree damage is positively correlated with June-October O3, as indicated by previous studies. Further analysis will explore the drivers of ecosystem impacts and roles of other natural and anthropogenic stressors, including variation in climatic water deficit. Understanding the consequences of prolonged O3 exposure on both individual trees and complex forest ecosystems helps identify the hidden environmental costs of tropospheric O3 and potential benefits of cleaner air.

  14. Cognitive Changes During Prolonged Exposure versus Prolonged Exposure Plus Cognitive Restructuring in Female Assault Survivors with Posttraumatic Stress Disorder

    ERIC Educational Resources Information Center

    Foa, Edna B.; Rauch, Sheila A. M.

    2004-01-01

    The authors report on changes in cognitions related to posttraumatic stress disorder (PTSD) among 54 female survivors of sexual and nonsexual assault with chronic PTSD who completed either prolonged exposure alone or in combination with cognitive restructuring. Treatment included 9-12 weekly sessions, and assessment was conducted at pretreatment,…

  15. LUNG INJURY AFTER OZONE EXPOSURE IS IRON-DEPENDENT

    EPA Science Inventory

    We tested the hypothesis that oxidative stress and biological effect after ozone (O3) exposure are dependent on changes in iron homeostasis. After O3 exposure, healthy volunteers demonstrated increased lavage concentrations of iron, transferrin, lactoferrin, and ferritin. In norm...

  16. Immunosuppression of pulmonary natural killer activity by exposure to ozone

    SciTech Connect

    Burleson, G.R.; Keyes, L.L.; Stutzman, J.D. )

    1989-01-01

    Ozone is an oxidant gas and an ubiquitous oxidant air pollutant with the potential to adversely affect pulmonary immune function with a consequent increase in disease susceptibility. Pulmonary natural killer (NK) activity was measured in order to assess the pulmonary immunotoxicity of continuous ozone exposure. Continuous ozone exposures at 1.0 ppm were performed for 23.5 hours per day for either 1, 5, 7, or 10 consecutive days. Pulmonary immune function was assessed by measuring natural killer (NK) activity from whole-lung homogenates of male Fischer-344 rats. Results of this study indicated that continuous ozone exposure for 1, 5, or 7 days resulted in a significant decrease in pulmonary NK activity. This suppressed pulmonary NK activity returned to control levels after continuous exposure to ozone for 10 days. The suppressed pulmonary NK response was thus attenuated and returned to normal values in the continued presence of ozone gas. This attenuation process is dynamic, complex, and doubtless involves several cell types and/or products of these cells. Pulmonary NK activity was also suppressed at 0.5 ppm ozone, but not at 0.1 ppm ozone, following 23.5 hours of exposure. NK activity is important for defense against viral, bacterial, and neoplastic disease. The depressed NK activity resulting from continuous ozone exposure could therefore result in a compromised ability to defend against pulmonary diseases.

  17. Media Impacts on Women's Fertility Desires: A Prolonged Exposure Experiment.

    PubMed

    Knobloch-Westerwick, Silvia; Willis, Laura E; Kennard, Ashley R

    2016-06-01

    Media exposure may have implications for family planning, a public health issue of key importance. Drawing on social comparison theory and social identity theory, a prolonged exposure experiment examined whether media portrayals of women's social roles affect fertility desires among 166 American, nonstudent, never married, childless women ages 21-35 years old. After sign-up and baseline sessions, participants viewed magazine pages five days in a row. Stimuli presented women in either mother/homemaker roles, beauty ideal roles, or professional roles. Three days later, participants again indicated their number of desired children and time planned until first birth. Exposure to mother/homemaker and beauty ideal portrayals increased the number of desired children across time. Exposure to professional portrayals increased the time planned until 1st birth compared to beauty ideal portrayals-this impact was partially mediated by a shift toward more progressive gender norms (per social identity theory) and assimilation (per social comparison theory). PMID:27166510

  18. Media Impacts on Women's Fertility Desires: A Prolonged Exposure Experiment.

    PubMed

    Knobloch-Westerwick, Silvia; Willis, Laura E; Kennard, Ashley R

    2016-06-01

    Media exposure may have implications for family planning, a public health issue of key importance. Drawing on social comparison theory and social identity theory, a prolonged exposure experiment examined whether media portrayals of women's social roles affect fertility desires among 166 American, nonstudent, never married, childless women ages 21-35 years old. After sign-up and baseline sessions, participants viewed magazine pages five days in a row. Stimuli presented women in either mother/homemaker roles, beauty ideal roles, or professional roles. Three days later, participants again indicated their number of desired children and time planned until first birth. Exposure to mother/homemaker and beauty ideal portrayals increased the number of desired children across time. Exposure to professional portrayals increased the time planned until 1st birth compared to beauty ideal portrayals-this impact was partially mediated by a shift toward more progressive gender norms (per social identity theory) and assimilation (per social comparison theory).

  19. Pulmonary function and clearance after prolonged sulfuric acid aerosol exposure

    SciTech Connect

    Ives, P.J. ); Gerrity, T.R.; DeWitt, P.; Folinsbee, L.J. )

    1991-03-15

    The authors studied pulmonary function and clearance responses after a 4 H exposure to 75-100 {mu}g/m{sup 3} sulfuric acid aerosol (SAA). Healthy subjects, who exercised for 30 min/H at ventilation of about 25 L/min, were exposed once to clean air and once to SAA. Oral hygiene and acidic juice gargle were used to minimize oral ammonia. Lung function tests, including spirometry, plethysmography, and partial flow-volume (PEFV) curves were performed before and after exposure. Clearance of 99m-Technetium labeled iron oxide was assessed after each exposure. The first moment of fractional tracheobronchial retention (M1TBR), after correcting for 24 H retention and normalizing to time zero, was used as an index of clearance. There were no significant changes in lung volumes, airways resistance, or maximum expiratory flows after SAA exposure. Flow at 40% of total lung capacity on PEFV curves decreased 17% (NS) after SAA exposure. Tracheobronchial clearance was accelerated after a single exposure to SAA; M1TBR decreased from 73 {plus minus} 5 min (air) to 69 {plus minus} 5 min (SAA). These results suggest that acute prolonged exposure to low levels of SAA has minimal effects on lung mechanics in healthy subjects but does produce a modest acceleration of particle clearance.

  20. Ozone exposure of human tracheal epithelial cells inactivates cyclooxygenase and increases 15-HETE production.

    PubMed

    Alpert, S E; Walenga, R W

    1995-12-01

    We assessed the immediate and prolonged effects of ozone on arachidonic acid (AA) metabolism by primary cultured human tracheal epithelial (TE) cells. TE monolayers were exposed at a gas-fluid interface to air or 0.1, 0.25, or 0.5 ppm ozone (15 min air, then 45 min air/ozone), and serially collected effluents were analyzed by thin-layer chromatography (TLC) and/or high-performance liquid chromatography. Release of prostaglandin E2 (PGE2) and AA, but not 15-hydroxyeicosatetraenoic acid (15-HETE) or its metabolites, was detected from cultures prelabeled with [14C]AA. PGE2 production, measured by immunoassay, was nearly constant during air exposure. In contrast, PGE2 increased two- to threefold during the first 15-min exposure to all concentrations of ozone, but then progressively declined to 78 +/- 17, 57 +/- 12 (P < or = 0.05), and 45 +/- 15% (P < or = 0.05) of air controls after exposure to 0.1, 0.25, and 0.5 ppm ozone. Ozone did not induce a new spectrum of AA metabolites; only PGE2, lesser amounts of PGF2 alpha, and 15-HETE were present in media and cell extracts of air- or ozone-exposed cultures provided with 30 microM exogenous AA. However, cyclooxygenase (CO) activity (PGE2 produced from 30 microM AA) decreased to 82 +/- 9, 53 +/- 8 (P < or = 0.05), and 28 +/- 6% (P < or = 0.05) vs. controls after 0.1, 0.25, and 0.5 ppm ozone, whereas 15-HETE production was unimpaired. When cells exposed to 0.5 ppm ozone were maintained for up to 6 h in 5% CO2-air, spontaneous PGE2 production remained decreased and recovery of CO activity was extremely slow. TLC analysis of lipid extracts from [14C]AA-labeled cells revealed a nearly twofold increase in free intracellular 15-HETE, and hydrolysis of phospholipids demonstrated increased esterified 15-HETE. Exposure of human TE cells to ozone leads to a transient increase followed by prolonged decrease in PGE2 production and increased intracellular retention of 15-HETE. Loss of the bronchodilator and anti-inflammatory properties

  1. PARAMETER EVALUATION AND MODEL VALIDATION OF OZONE EXPOSURE ASSESSMENT USING HARVARD SOUTHERN CALIFORNIA CHRONIC OZONE EXPOSURE STUDY DATA

    EPA Science Inventory

    To examine factors influencing long-term ozone exposures by children living in urban communities, we analyzed longitudinal data on personal, indoor, and outdoor ozone concentrations as well as related housing and other questionnaire information collected in the one-year-long Harv...

  2. Cerebellar morphological alterations in rats induced by prenatal ozone exposure.

    PubMed

    Rivas-Manzano, P; Paz, C

    1999-11-26

    The present study analyzes the morphological aspects of the cerebellum of rats with prenatal exposure to ozone. A double blind histological and planimetric analysis was performed studying sagittal sections of the anterior cerebellar lobe at postnatal days 0, 12 and 60. Ozone exposed rats showed cerebellar necrotic signs at age 0, diminished area of the molecular layer with Purkinje cells with pale nucleoli and perinucleolar bodies at age 12, and Purkinje cells showing nuclei with unusual clumps of chromatin in the periphery at age 60. We conclude that exposure to high concentrations of ozone during gestation induces permanent cerebellar damage in rats.

  3. Interannual Variability of Ozone and Ultraviolet Exposure

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Piacentini, R. D.; Ziemke, J.; Celarier, E.; Larko. D.

    1999-01-01

    Annual zonal averages of ozone amounts from Nimbus-7/TOMS (Total Ozone Mapping Spectrometer) (1979 to 1992) are used to estimate the interannual variability of ozone and UVB (290 - 315 nm) irradiance between plus or minus 60 deg. latitude. Clear-sky interannual ozone and UVB changes are mainly caused by the Quasi Biennial Oscillation (QBO) of stratospheric winds, and can amount to plus or minus 15% at 300 nm and plus or minus 5% at 310 nm (or erythemal irradiance) at the equator and at middle latitudes. Near the equator, the interannual variability of ozone amounts and UV irradiance caused by the combination of the 2.3 year QBO and annual cycles implies that there is about a 5-year periodicity in UVB variability. At higher latitudes, the appearance of the interannual UVB maximum is predicted by the QBO, but without the regular periodicity. The 5-year periodic QBO effects on UVB irradiance are larger than the currently evaluated long-term changes caused by the decrease in ozone amounts.

  4. Exposure to ozone reduces influenza disease severity and alters distribution of influenza viral antigens in murine lungs

    SciTech Connect

    Wolcott, J.A.; Zee, Y.C,; Osebold, J.W.

    1982-09-01

    Exposure to ambient levels of ozone (0.5 ppm) was shown to alter the pathogenesis of respiratory infection after aerosol infection of mice with influenza A virus. A semiquantitative method for determination of the sites of virus replication by direct immunofluorescence indicated that exposure to ozone reduced the involvement of respiratory epithelium in the infectious process and resulted in a less widespread infection of the alveolar parenchyma. Furthermore, the ozone-mediated alteration in viral antigen distribution was consistent with significantly reduced influenza disease mortality and prolonged survival time, but only when the oxidant was present during the course of infection. Reduced disease severity in ozone-exposed animals appeared to be independent of peak pulmonary virus titers, pulmonary interferon titers, and pulmonary and serum-neutralizing antibody titers. These studies suggested that the distribution of influenza virus in the murine lung was a key factor in disease severity.

  5. Exposure to ozone and erythrocyte osmotic resistance in the rat

    SciTech Connect

    Ikemi, Y.; Ohmori, K.; Ito, T.; Osaka, F.; Matuura, Y. )

    1992-10-01

    In order to learn the biological effect of photochemical oxidants on living bodies, we exposed newborn and adult rats, of both sexes, to ozone at a concentration of 0.25 ppm, which can be encountered in an urban environment, and then measured the osmotic resistance of their erythrocytes. The results of experiments using newborn rats indicated a positive increase in the osmotic resistance of erythrocytes in whole blood following ozone exposure for 4 weeks. An increase in the osmotic resistance of erythrocytes in the top part obtained by centrifugation was observed following ozone exposure for 12 weeks. This tendency was especially evident among male rats. On the other hand, no increase in the osmotic resistance of erythrocytes was recognized in the adult animals which had been exposed to the same concentration of ozone for 18 months.

  6. Growth-stage dependent crop yield response to ozone exposure.

    PubMed

    Younglove, T; McCool, P M; Musselman, R C; Kahl, M E

    1994-01-01

    Data from four crop yield-loss field trials were examined to determine if analysis using an imposed phenological weighting function based on seasonal growth stage would provide a more accurate indication of impact of ozone exposure. Alfalfa (Medicago sativa L. cv. Moapa 69), dry bean (Phaseolus vulgaris L. cv. California Dark Red kidney), fresh market and processing tomato (Lycopersicon esculentum Mill. cv. 6718 VF and VF-145-B7879, respectively) were grown at 9-11 ambient field plots within southern California comprising an ambient gradient of ozone. The growing season for each crop was artificially divided into 'quarters' composed of equal numbers of whole days and roughly corresponding to specific growth stages. Ozone exposure was calculated for each of these 'quarters' and regressed against final crop yield using 163 different exposure statistics. Weighting functions were developed using reciprocal residual mean square (1/RMS) or percentage of the best 100 exposure statistics of the 163 tested (TOP100) for each of the quarters. The third quarter of the alfalfa season was clearly most responsive to ozone as measured by both of the weighting functions. Third quarter ozone was also weighted highest by both weighting functions for dry bean. Fresh market and processing tomato were each influenced the greatest by second quartero zone as demonstrated by both weighting functions. The occurrence of ozone during physiologically important events (flowering and initial fruit set in second quarter for tomato; pod development in third quarter for dry bean) appeared to influence the yield of these crops the greatest. Growth-stage-dependent phenological weighting of pollutant exposure may result in more effective predictions of levels of ozone exposure resulting in yield reductions.

  7. Predictors of individual differences in acute response to ozone exposure

    SciTech Connect

    McDonnell, W.F.; Muller, K.E.; Bromberg, P.A.; Shy, C.M. )

    1993-04-01

    The purpose of this study was to identify personal characteristics that predict individual differences in acute FEV1 response to ozone exposure. Response and predictor data were collected on 290 white male volunteers 18 to 32 yr of age who were each exposed to one of six concentrations of ozone between 0.0 and 0.40 part per million. The sample was divided into an exploratory sample of 96 and a confirmatory sample of 194 subjects. Exploratory analysis indicated that ozone, age, and several other variables explained a significant proportion of the variance in response. In the confirmatory sample, only age and ozone concentration predicted FEV1 decrement. For the combined sample ozone explained 31% of the variance, with age accounting for an additional 4%. The model predicted a decreasing response with increasing age for all nonzero ozone concentrations. For exposure to 0.40 ppm, the model predicts decrements in FEV1 of 1.07 and 0.47 L for 18- and 30-yr-old subjects, respectively. We concluded that for white male subjects age was a significant predictor of response, with older subjects being less responsive to ozone. Furthermore, we demonstrated that exploratory analysis without control of type I statistical error rates may result in apparent findings that cannot be replicated.

  8. Alterations in surfactant protein A after acute exposure to ozone.

    PubMed

    Su, W Y; Gordon, T

    1996-05-01

    The surfactant layer covering the gas-exchange region of the lung serves as the initial site of interaction with inhaled oxidant gases. Among the endogenous compounds potentially vulnerable to oxidative injury are surfactant proteins. This study focused on the effect of ozone on surfactant protein A (SP-A) function, content, and gene expression. To determine the time course of response to ozone, guinea pigs were exposed to 0.2-0.8 parts/million (ppm) ozone for 6 h and were killed up to 120 h postexposure. To determine the effect of repeated exposure, animals were exposed to 0.8 ppm ozone for 6 h/day and were killed on days 3 and 5. A significant increase in surfactant's ability to modulate the respiratory burst induced by phorbol 12-myristate 13-acetate in naive macrophages was observed at 24 h after a single 0.8 ppm ozone exposure. Because neutralizing antibodies to SP-A blunted this stimulatory effect, we hypothesized that ozone enhanced the modulatory role of SP-A in macrophage function. This alteration in function was accompanied by an influx of inflammatory cells and only marginal changes in SP-A levels as determined by an enzyme-linked immunosorbent assay. No significant changes in steady-state levels of SP-A mRNA were observed after single or repeated exposure to ozone. Thus the inflammation that accompanies in vivo ozone exposure may result in a change in the structure and thus functional role of SP-A in modulating macrophage activity.

  9. Some consequences of ozone exposure on health.

    PubMed

    Paz, C

    1997-01-01

    The reaction of ozone with polyunsaturated fatty acids from the surfactant factor and pulmonary epithelial cells produces different reaction products which can cross the alveolar-capillary barrier and reach distant structures. Although only a few papers claim extrapulmonary changes in animals exposed to this gas, some neurological deficits, such as complaints of fatigue, lethargy, headache in humans, as well as significant disarrangements in the sleep pattern related to biochemical changes in the brain have been referred to in animals exposed to ozone. In the present review, the molecular configuration and the reaction of ozone at different lung levels are related to impairment at the respiratory and blood systems, in order to elucidate the mechanisms by which this gas or its reaction products, such as free radicals, prostaglandins and others can cross the alveolar-capillary and hemato-encephalic barriers, and to explain those neurological effects.

  10. The role of ozone exposure in the epidemiology of asthma

    SciTech Connect

    Balmes, J.R.

    1993-12-01

    Asthma is a clinical condition characterized by intermittent respiratory symptoms, nonspecific airway hyperresponsiveness, and reversible airway obstruction. Although the pathogenesis of asthma is incompletely understood, it is clear that airway inflammation is a paramount feature of the condition. Because inhalation of ozone by normal, healthy subjects causes increased airway responsiveness and inflammation, it is somewhat surprising that most controlled human exposure studies that have involved asthmatic subjects have not shown them to be especially sensitive to ozone. The acute decrement in lung function that is the end point traditionally used to define sensitivity to ozone in these studies may be due more to neuromuscular mechanisms limiting deep inspiration than to bronchoconstriction. The frequency of asthma attacks following ozone exposures may be a more relevant end point. Epidemiologic studies, rather than controlled human exposure studies, are required to determine whether ozone pollution increases the risk of asthma exacerbations. Asthma affects approximately 10 million people in the United States and, thus, the answer to this question is of considerable public health importance. Both the prevalence and severity of asthma appear to be increasing in many countries. Although increased asthma morbidity and mortality are probably of multifactorial etiology, a contributory role of urban air pollution is plausible. The epidemiologic database to support an association between asthma and ozone exposure is limited, but the results of several studies suggest such an association. Some potential approaches to further investigation of the relationship between asthma and ozone, including those that would link controlled human exposures to population-based studies, are considered. 57 refs.

  11. Ozone exposure increases respiratory epithelial permeability in humans

    SciTech Connect

    Kehrl, H.R.; Vincent, L.M.; Kowalsky, R.J.; Horstman, D.H.; O'Neil, J.J.; McCartney, W.H.; Bromberg, P.A.

    1987-05-01

    Ozone is a respiratory irritant that has been shown to cause an increase in the permeability of the respiratory epithelium in animals. We used inhaled aerosolized /sup 99m/Tc-labeled diethylene triamine pentacetic acid (/sup 99m/Tc-DTPA) to investigate whether human respiratory epithelial permeability is similarly affected by exposure to ozone. In a randomized, crossover double-blinded study, 8 healthy, nonsmoking young men were exposed for 2 h to purified air and 0.4 ppm ozone while performing intermittent high intensity treadmill exercise (minute ventilation = 66.8 L/min). SRaw and FVC were measured before and at the end of exposures. Seventy-five minutes after the exposures, the pulmonary clearance of /sup 99m/Tc-DTPA was measured by sequential posterior lung imaging with a computer-assisted gamma camera. Ozone exposure caused respiratory symptoms in all 8 subjects and was associated with a 14 +/- 2.8% (mean +/- SEM) decrement in FVC (p less than 0.001) and a 71 +/- 22% increase in SRaw (p = 0.04). Compared with the air exposure day, 7 of the 8 subjects showed increased /sup 99m/Tc-DTPA clearance after the ozone exposure, with the mean value increasing from 0.59 +/- 0.08 to 1.75 +/- 0.43%/min (p = 0.03). These data show that ozone exposure sufficient to produce decrements in the pulmonary function of human subjects also causes an increase in /sup 99m/Tc-DTPA clearance.

  12. Exposure-Relevant Ozone Chemistry in Occupied Spaces

    SciTech Connect

    Coleman, Beverly Kaye

    2009-04-01

    Ozone, an ambient pollutant, is transformed into other airborne pollutants in the indoor environment. In this dissertation, the type and amount of byproducts that result from ozone reactions with common indoor surfaces, surface residues, and vapors were determined, pollutant concentrations were related to occupant exposure, and frameworks were developed to predict byproduct concentrations under various indoor conditions. In Chapter 2, an analysis is presented of secondary organic aerosol formation from the reaction of ozone with gas-phase, terpene-containing consumer products in small chamber experiments under conditions relevant for residential and commercial buildings. The full particle size distribution was continuously monitored, and ultrafine and fine particle concentrations were in the range of 10 to>300 mu g m-3. Particle nucleation and growth dynamics were characterized.Chapter 3 presents an investigation of ozone reactions with aircraft cabin surfaces including carpet, seat fabric, plastics, and laundered and worn clothing fabric. Small chamber experiments were used to determine ozone deposition velocities, ozone reaction probabilities, byproduct emission rates, and byproduct yields for each surface category. The most commonly detected byproducts included C1?C10 saturated aldehydes and skin oil oxidation products. For all materials, emission rates were higher with ozone than without. Experimental results were used to predict byproduct exposure in the cabin and compare to other environments. Byproduct levels are predicted to be similar to ozone levels in the cabin, which have been found to be tens to low hundreds of ppb in the absence of an ozone converter. In Chapter 4, a model is presented that predicts ozone uptake by and byproduct emission from residual chemicals on surfaces. The effects of input parameters (residue surface concentration, ozone concentration, reactivity of the residue and the surface, near-surface airflow conditions, and

  13. Examining potential contraindications for prolonged exposure therapy for PTSD

    PubMed Central

    van Minnen, Agnes; Harned, Melanie S.; Zoellner, Lori; Mills, Katherine

    2012-01-01

    Although prolonged exposure (PE) has received the most empirical support of any treatment for post-traumatic stress disorder (PTSD), clinicians are often hesitant to use PE due to beliefs that it is contraindicated for many patients with PTSD. This is especially true for PTSD patients with comorbid problems. Because PTSD has high rates of comorbidity, it is important to consider whether PE is indeed contraindicated for patients with various comorbid problems. Therefore, in this study, we examine the evidence for or against the use of PE with patients with problems that often co-occur with PTSD, including dissociation, borderline personality disorder, psychosis, suicidal behavior and non-suicidal self-injury, substance use disorders, and major depression. It is concluded that PE can be safely and effectively used with patients with these comorbidities, and is often associated with a decrease in PTSD as well as the comorbid problem. In cases with severe comorbidity, however, it is recommended to treat PTSD with PE while providing integrated or concurrent treatment to monitor and address the comorbid problems. PMID:22893847

  14. Ozone exposure alters tracheobronchial mucociliary function in humans

    SciTech Connect

    Foster, W.M.; Costa, D.L.; Langenback, E.G.

    1987-09-01

    Mucociliary function is a primary defense mechanism of the tracheobronchial airways, and yet the response of this system to an inhalational hazard, such as ozone, is undefined in humans. Utilizing noninvasive techniques to measure deposition and retention of insoluble radiolabeled particles on airway mucous membranes, we studied the effect on mucus transport of 0.2 and 0.4 ppm ozone compared with filtered air (FA) in seven healthy males. During 2-h chamber exposures, subjects alternated between periods of rest and light exercise with hourly spirometric measurement of lung function. Mechanical and mucociliary function responses to ozone by lung airways appeared concentration dependent. Reduction in particle retention was significant (P less than 0.005) (i.e., transport of lung mucus was increased during exposure to 0.4 ppm ozone and was coincident with impaired lung function; e.g., forced vital capacity and midmaximal flow rate fell by 12 and 16%, respectively, and forced expiratory volume at 1 s by 5%, of preexposure values). Regional analysis indicated that mucus flow from distal airways into central bronchi was significantly increased (P less than 0.025) by 0.2 ppm ozone. This peripheral effect, however, was buffered by only a marginal influence of 0.2 ppm ozone on larger bronchi, such that the resultant mucus transport for all airways of the lung in aggregate differed only slightly from FA exposures. These data may reflect differences in regional diffusion of ozone along the respiratory tract, rather than tissue sensitivity. In conclusion, mucociliary function of humans is acutely stimulated by ozone and may result from fluid additions to the mucus layer from mucosal and submucosal secretory cells and/or alteration of epithelial permeability.

  15. Ozone exposure alters tracheobronchial mucociliary function in humans.

    PubMed

    Foster, W M; Costa, D L; Langenback, E G

    1987-09-01

    Mucociliary function is a primary defense mechanism of the tracheobronchial airways, and yet the response of this system to an inhalational hazard, such as ozone, is undefined in humans. Utilizing noninvasive techniques to measure deposition and retention of insoluble radiolabeled particles on airway mucous membranes, we studied the effect on mucus transport of 0.2 and 0.4 ppm ozone compared with filtered air (FA) in seven healthy males. During 2-h chamber exposures, subjects alternated between periods of rest and light exercise with hourly spirometric measurement of lung function. Mechanical and mucociliary function responses to ozone by lung airways appeared concentration dependent. Reduction in particle retention was significant (P less than 0.005) (i.e., transport of lung mucus was increased during exposure to 0.4 ppm ozone and was coincident with impaired lung function; e.g., forced vital capacity and midmaximal flow rate fell by 12 and 16%, respectively, and forced expiratory volume at 1 s by 5%, of preexposure values). Regional analysis indicated that mucus flow from distal airways into central bronchi was significantly increased (P less than 0.025) by 0.2 ppm ozone. This peripheral effect, however, was buffered by only a marginal influence of 0.2 ppm ozone on larger bronchi, such that the resultant mucus transport for all airways of the lung in aggregate differed only slightly from FA exposures. These data may reflect differences in regional diffusion of ozone along the respiratory tract, rather than tissue sensitivity. In conclusion, mucociliary function of humans is acutely stimulated by ozone and may result from fluid additions to the mucus layer from mucosal and submucosal secretory cells and/or alteration of epithelial permeability.

  16. Ozone NAAQS Review: Risk/Exposure Assessment

    EPA Science Inventory

    Ozone is one of the six major air pollutants for which EPA has issued air quality criteria and established national ambient air quality standards (NAAQS) based on those criteria. The Clear Air Act (CAA) requires EPA to periodically review and revise, as appropriate, existing air ...

  17. Ozone’s Impact on Public Health: Contributions from Indoor Exposures to Ozone and Products of Ozone-Initiated Chemistry

    PubMed Central

    Weschler, Charles J.

    2006-01-01

    Objective The associations between ozone concentrations measured outdoors and both morbidity and mortality may be partially due to indoor exposures to ozone and ozone-initiated oxidation products. In this article I examine the contributions of such indoor exposures to overall ozone-related health effects by extensive review of the literature as well as further analyses of published data. Findings Daily inhalation intakes of indoor ozone (micrograms per day) are estimated to be between 25 and 60% of total daily ozone intake. This is especially noteworthy in light of recent work indicating little, if any, threshold for ozone’s impact on mortality. Additionally, the present study estimates that average daily indoor intakes of ozone oxidation products are roughly one-third to twice the indoor inhalation intake of ozone alone. Some of these oxidation products are known or suspected to adversely affect human health (e.g., formaldehyde, acrolein, hydroperoxides, fine and ultrafine particles). Indirect evidence supports connections between morbidity/mortality and exposures to indoor ozone and its oxidation products. For example, cities with stronger associations between outdoor ozone and mortality tend to have residences that are older and less likely to have central air conditioning, which implies greater transport of ozone from outdoors to indoors. Conclusions Indoor exposures to ozone and its oxidation products can be reduced by filtering ozone from ventilation air and limiting the indoor use of products and materials whose emissions react with ozone. Such steps might be especially valuable in schools, hospitals, and childcare centers in regions that routinely experience elevated outdoor ozone concentrations. PMID:17035131

  18. Airway response to ultra short-term exposure to ozone

    SciTech Connect

    Fouke, J.M.; Delemos, R.A.; McFadden, E.R. Jr.

    1988-02-01

    To determine whether acute short-term exposure to oxidant pollutants can cause changes in respiratory mechanics, we gave 0.5 ppm ozone for 5 min to 7 baboons. We measured pulmonary resistance (RL) and obtained dose response curves to methacholine before and after the exposures. This brief insult increased resistance (control RL = 1.53 +/- 0.21 cm H/sub 2/O.L-1 s; post-ozone RL = 3.53 +/- 0.54 cm H/sub 2/O.L-1 s). On a second occasion, 6 of these animals were restudied before and after the administration of cromolyn sodium. Although this drug had no effect on the measurements of mechanics made in the control period, it significantly reduced the ozone-induced changes in mechanics. The increase in RL was 52% of that produced in the first study. The results demonstrated that the ozone injury with its acute and subacute airway sequelae occurs quite rapidly and after very brief exposure. The time course of the change in mechanics and the effects of cromolyn suggest the hypothesis that surface epithelial cells are disrupted, causing subsequent release of bronchoconstricting agents.

  19. Adaptation of extrapulmonary responses to ozone exposure in conscious rats.

    PubMed

    Iwasaki, T; Takahashi, M; Saito, H; Arito, H

    1998-01-01

    The adaptation of cardiovascular and thermoregulatory responses to ozone (O3) was examined by repeated exposure of electrocardiographic (ECG) electrode- and thermistor sensor-implanted rats to O3 for 4 consecutive days (8 hrs/day). Circadian rhythms of heart rate (HR) and abdominal core temperature (Tco) were disrupted on the first and second O3 exposure days in a concentration dependent manner. The 8-hr and 12-hr averaged values of HR and Tco during the exposure period and the dark post-exposure period, respectively, decreased significantly on the first and second exposure days. The decreased HR and Tco recovered to respective control values after small but significant rebound increases on the third and fourth days of O3 exposure. The adaptation of the extrapulmonary responses to O3 exposure was discussed in light of the previously reported time periods required to abolish the spontaneous breathing, biochemical, cellular, and morphological responses to O3.

  20. Attenuated response to repeated daily ozone exposures in asthmatic subjects

    SciTech Connect

    Gong, H. Jr.; Linn, W.S.; McManus, M.S.

    1997-01-01

    The development of attenuated response ({open_quotes}tolerance{close_quotes}) to daily ozone (O{sub 3}) exposures in the laboratory is well established in healthy adult volunteers. However, the capability of asthmatics to develop tolerance during multiday ozone exposures in unclear. We exposed 10 adult volunteers with mild asthma to 0.4 ppm O{sub 3} in filtered air for 3 h/d on 5 consecutive d. Two similar filtered-air exposures during the preceding week served as controls. Follow-up O{sub 3} exposures were performed 4 and 7 d after the most recent consecutive exposure. All exposures were performed in an environmental chamber at 31 {degrees}C and 35% relative humidity. The subjects performed moderate exercise (mean ventilation rate of 32 l/min) for 15 min of each half-hour. Responses were measured with spirometry and symptom evaluations before and after each exposure, and a bronchial reactivity test (methacholine challenge) was conducted after each exposure. All response measurements showed clinically and statistically significant day-to-day variation. Symptom and forced-expiratory-volume-in-1-s responses were similarly large on the 1st and 2nd O{sub 3} exposure days, after which they diminished progressively, approaching filtered air response levels by the 5th consecutive O{sub 3} day. This tolerance was partially lost 4 and 7 d later. Bronchial reactivity peaked after the first O{sub 3} exposure and remained somewhat elevated after all subsequent O{sub 3} exposures, relative to its control level following filtered-air exposures. Individual responses varied widely; more severe initial responses to O{sub 3} predicted less rapid attenuation. We concluded that asthmatics can develop tolerance to frequent high-level O{sub 3} exposures in much the same manner as normal subjects, although the process may be slower and less fully effective in asthmatics. 27 refs., 3 figs., 4 tabs.

  1. PLASMA AND LUNG MACROPHAGE CAROTENOID RESPONSIVENESS TO SUPPLEMENTATION AND OZONE EXPOSURE IN HUMANS

    EPA Science Inventory

    OBJECTIVE:: To examine the effect of ozone exposure and vegetable juice supplementation on plasma and lung macrophage concentrations of carotenoids. DESIGN:: A randomized trial. SETTING:: Subjects were exposed to ambient air prior to antioxidant supplementation and to ozone after...

  2. A comparison of Narrative Exposure Therapy and Prolonged Exposure therapy for PTSD.

    PubMed

    Mørkved, N; Hartmann, K; Aarsheim, L M; Holen, D; Milde, A M; Bomyea, J; Thorp, S R

    2014-08-01

    The purpose of this review was to compare and contrast Prolonged Exposure (PE) and Narrative Exposure Therapy (NET). We examined the treatment manuals to describe the theoretical foundation, treatment components, and procedures, including the type, manner, and focus of exposure techniques and recording methods used. We examined extant clinical trials to investigate the range of treatment formats reported, populations studied, and clinical outcome data. Our search resulted in 32 studies on PE and 15 studies on NET. Consistent with prior reviews of PTSD treatment, it is evident that PE has a solid evidence base and its current status as a first line treatment for the populations studied to this date is warranted. We argue that NET may have advantages in treating complex traumatization seen in asylum seekers and refugees, and for this population NET should be considered a recommended treatment. NET and PE have several commonalities, and it is recommended that studies of these treatments include a broader range of populations and trauma types to expand the current knowledge on the treatment of PTSD.

  3. Prolonged noise exposure-induced auditory threshold shifts in rats

    PubMed Central

    Chen, Guang-Di; Decker, Brandon; Muthaiah, Vijaya Prakash Krishnan; Sheppard, Adam; Salvi, Richard

    2014-01-01

    Noise-induced hearing loss (NIHL) initially increases with exposure duration, but eventually reaches an asymptotic threshold shift (ATS) once the exposure duration exceeds 18-24 h. Equations for predicting the ATS have been developed for several species, but not for rats, even though this species is extensively used in noise exposure research. To fill this void, we exposed rats to narrowband noise (NBN, 16-20 kHz) for 5 weeks starting at 80 dB SPL in the first week and then increasing the level by 6 dB per week to a final level of 104 dB SPL. Auditory brainstem responses (ABR) were recorded before, during, and following the exposure to determine the amount of hearing loss. The noise induced threshold shift to continuous long-term exposure, defined as compound threshold shift (CTS), within and above 16-20 kHz increased with noise level at the rate of 1.82 dB threshold shift per dB of noise level (NL) above a critical level (C) of 77.2 dB SPL i.e. CTS = 1.82(NL-77.2). The normalized amplitude of the largest ABR peak measured at 100 dB SPL decreased at the rate of 3.1% per dB of NL above the critical level of 76.9 dB SPL, i.e., %ABR Reduction = 3.1%(NL-76.9). ABR thresholds measured >30 days post-exposure only partially recovered resulting in a permanent threshold shift of 30-40 dB along with severe hair cell loss in the basal, high-frequency region of the cochlea. In the rat, CTS increases with noise level with a slope similar to humans and chinchillas. The critical level (C) in the rat is similar to that of humans, but higher than that of chinchillas. PMID:25219503

  4. Response of the rat erythrocyte to ozone exposure

    NASA Technical Reports Server (NTRS)

    Larkin, E. C.; Kimzey, S. L.; Siler, K.

    1978-01-01

    Sprague-Dawley rats were exposed to high (6-8 ppm) and moderate (1.5 ppm) amounts of ozone (O3) for various time periods. Response of the rat erythrocyte to ozone was monitored with red blood cell potassium (rubidium) influx studies, with storage stress combined with ultrastructural studies and with levels of erythrocyte glutathione peroxidase and superoxide dismutase. Erythrocytes of rats exposed to O3 showed no significant changes either in their potassium influx or in their glutathione peroxidase and superoxide dismutase activities compared to controls. Erythrocyte differential counts on O3-exposed animals showed significant changes initially as well as following storage stress compared to controls. Rats exposed to 8 ppm O3 for 4 h showed a marked increase in echinocytes. These consistent transformations from discocytes to echinocytes following O3 exposure suggest latent erythrocyte damage has occurred.

  5. Preexposure to low ozone concentrations does not diminish the pulmonary function response on exposure to higher ozone concentrations

    SciTech Connect

    Gliner, J.A.; Horvath, S.M.; Folinsbee, L.J.

    1983-01-01

    To determine whether persons repeatedly exposed to low ozone concentrations would demonstrate a diminished responsivity, as a result of adaptation or desensitization, when subsequently exposed to a higher ozone concentration, we performed the following study. Respiratory sensitivity (pulmonary function response) to 2 h of exposure to 0.42 or 0.50 ppm ozone (acute exposure) was determined 3 months before or 6 to 8 wk after the study. Twenty-one subjects (8 men, 13 women) were exposed for 2 h or 5 consecutive days to filtered air, 0.20, 0.20, 0.20, and 0.42 to 0.50 ppm ozone, respectively. There were no significant differences between the responses of men and women to ozone. Subjects were divided into a sensitive group (greater than 20% drop in FEV1) and a nonsensitive group (less than 10% drop in FEV1) on the basis of their responses to the acute exposure. Neither the overall group nor the nonsensitive group showed a significant response to 0.20 ppm. Sensitive subjects (n . 9) showed small but significant decreases in FEV1 on exposure to 0.20 ppm. The predominant finding was that the 3 days of preexposure to 0.20 ppm ozone had no effect on the response to 0.42 or 0.50 ppm ozone on the fourth day (when compared with the previous acute exposure to 0.42 or 0.50 ppm). We conclude that subjects repeatedly (3 times) exposed to a low (0.20 ppm) concentration of ozone do not demonstrate a pulmonary function adaptation or desensitization on a subsequent exposure to a higher (0.42 or 0.50 ppm) ozone concentration.

  6. USE OF AUXILIARY DATA FOR SPATIAL INTERPOLATION OF OZONE EXPOSURE IN SOUTHEASTERN FORESTS

    EPA Science Inventory

    In order to assess the impact of tropospheric ozone on forests, it is necessary to quantify ozone exposure on regional scales. Since ozone monitoring stations are widely scattered and mostly concentrate in urban and suburban areas, some form of spatial interpolation is necessary ...

  7. Ozone exposure activates oxidative stress responses in murine skin.

    PubMed

    Valacchi, Giuseppe; van der Vliet, Albert; Schock, Bettina C; Okamoto, Tatsuya; Obermuller-Jevic, Ute; Cross, Carroll E; Packer, Lester

    2002-09-30

    Ozone (O(3)) is among the most reactive environmental oxidant to which skin is exposed. O(3) exposure has previously been shown to induce antioxidant depletion as well as lipid and protein oxidation in the outermost skin layer, the stratum corneum (SC), but little is known regarding the potential effects of O(3) on the skin epidermis and dermis. To evaluate such skin responses to O(3), SKH-1 hairless mice were exposed for 2 h to 8.0 ppm O(3) or to ambient air. O(3) exposure caused a significant increase in skin carbonyls (28%) compared to the skin of air exposed control animals. An evident increase in 4-hydroxynonenal-protein adducts was detected after O(3) exposure. O(3) exposure caused a rapid up-regulation of HSP27 (20-fold), and more delayed induction of HSP70 (2.8-fold) and heme oxygenase-1 (5-fold). O(3) exposure also led to the induction of nitric oxide synthase (iNOS) 6-12 h following O(3) exposure. We conclude that skin exposure to high levels of O(3) not only affects antioxidant levels and oxidation markers in the SC, but also induces stress responses in the active layers of the skin, most likely by indirect mechanisms, since it is unlikely that O(3) itself penetrates the protective SC layers.

  8. Ozone decreases spring root growth and root carbohydrate content in ponderosa pine the year following exposure

    SciTech Connect

    Andersen, C.P.; Hogsett, W.E.; Wessling, R.; Plocher, M.

    1991-01-01

    Storage carbohydrates are extremely important for new shoot and root development following dormancy or during periods of high stress. The hypothesis that ozone decreases carbohydrate storage and decreases new root growth during the year following exposure was investigated. The results suggest that (1) ponderosa pine seedlings exposed to 122 and 169 ppm hrs ozone for one season have significantly less root starch reserves available just prior to and during bud break the following year, and (2) spring root growth is decreased following ozone exposure. The carry-over effects of ozone stress may be important in long-lived perennial species which are annually subjected to ozone.

  9. Thyroid hormone responses to prolonged cold exposure in man

    PubMed Central

    Eastman, C. J.; Ekins, R. P.; Leith, I. M.; Williams, E. S.

    1974-01-01

    1. Four men, of ages varying from 23 to 28 years, living at Halley Bay, Antarctica (75° 31′ S, 26° 39′ W), were exposed to a mean air temperature of 6·6° C. 2. The concentration of serum triiodothyronine (T3) rose significantly by the second day, remained raised, and returned to pre-exposure levels within 2 days of return to a normal environment. 3. The concentration of serum thyroxine (T4) rose more slowly than did the T3, reaching a maximum in 3-4 days and also returning to normal within 2 days of return to a normal environment. 4. There was a wide individual variation in the change of concentration of serum cortisol. PMID:4422816

  10. A study of the spatiotemporal health impacts of ozone exposure.

    PubMed

    Christakos, G; Kolovos, A

    1999-01-01

    Exposure analysis and mapping of spatiotemporal pollutants in relation to their health effects are important challenges facing environmental health scientists and integrated assessment modellers. In this work, a methodological framework is discussed to study the impact of spatiotemporal ozone (O3) exposure distributions on the health of human populations. The framework, however, is very general and can be used to study various other pollutants. The spatiotemporal analysis starts with exposure distributions producing the input to pollutokinetic (or toxicokinetic) laws which are linked to effect models which, in turn, are integrated with relationships that describe how effects are distributed across populations. Important characteristics of the environmental health framework are holisticity and stochasticity. Holisticity emphasizes the functional relationships between composite space/time O3 maps, pollutokinetic models of burden on target organs and tissues, and health effects. These relationships offer a meaningful physical interpretation of the exposure and biological processes that affect human exposure. Stochasticity involves the rigorous representation of natural uncertainties and biological variations in terms of spatiotemporal random fields. The stochastic perspective introduces a deeper epistemological understanding in the development of improved models of spatiotemporal human exposure analysis and mapping. Also, it explicitly determines the knowledge bases available and develops logically plausible rules and standards for data processing and human exposure map construction. The proposed approach allows the horizontal integration among sciences related to the human exposure problem that leads to accurate and informative spatiotemporal maps of O3 exposure and effect distributions and an integrative analysis of the whole risk case. By processing a variety of knowledge bases, the spatiotemporal analysis can bring together several sciences which are all relevant

  11. Persistent and Unusual Respiratory Findings after Prolonged Glutaraldehyde Exposure.

    PubMed

    Copeland, S; Nugent, K

    2015-07-01

    Glutaraldehyde is commonly used in endoscopy labs to clean and disinfect instruments. It can cause direct irritation of the skin and the upper and lower airways. Health care workers are also at risk for the development of irritant-induced or sensitizer-induced occupational asthma when exposed to this chemical. Herein, we report on a patient who had frequent exposures to glutaraldehyde over one year while working in an endoscopy lab and developed chronic upper and lower respiratory tract symptoms. Multiple spirometric tests during her evaluation revealed variable results including restrictive pattern with a response to bronchodilators, obstructive pattern with a paradoxic bronchoconstrictive response to bronchodilators, and obstructive pattern with a partial response to bronchodilators. These results indicate that the distribution of inflammation and bronchial responsiveness can vary in a single patient with glutaraldehyde-induced occupational asthma. Therefore, the evaluation may be more difficult than might be expected in patients with occupational asthma, and some patients will need multiple pulmonary function tests to characterize their airway disease.

  12. Hippocampal damage associated with prolonged glucocorticoid exposure in primates.

    PubMed

    Sapolsky, R M; Uno, H; Rebert, C S; Finch, C E

    1990-09-01

    In the laboratory rat and guinea pig, glucocorticoids (GCs), the adrenal steroids that are secreted during stress, can damage the hippocampus and exacerbate the hippocampal damage induced by various neurological insults. An open question is whether GCs have similar deleterious effects in the primate hippocampus. In fact, we showed that sustained and fatal stress was associated with preferential hippocampal damage in the vervet monkey; however, it was not possible to determine whether the excessive GC secretion that accompanied such stress was the damaging agent. The present study examines this possibility. Pellets of cortisol (the principal GC of primates) were stereotaxically implanted into hippocampi of 4 vervet monkeys; contralateral hippocampi were implanted with cholesterol pellets as a control. One year later at postmortem, preferential damage occurred in the cortisol-implanted side. In the cholesterol side, mild cell layer irregularity was noted in 2 of 4 cases. By contrast in the cortisol-exposed hippocampi, all cases had at least 2 of the following neuropathologic markers: cell layer irregularity, dendritic atrophy, soma shrinkage and condensation, or nuclear pyknosis. Damage was severe in some cases, and was restricted to the CA3/CA2 cellfield. This anatomical distribution of damage, and the cellular features of the damage agree with that observed in instances of GC-induced toxicity in the rodent hippocampus, and of stress-induced toxicity in the primate hippocampus. These observations suggest that sustained GC exposure (whether due to stress, Cushings syndrome or exogenous administration) might damage the human hippocampus.

  13. Effects of varying environmental conditions on vegetation response to ozone exposure

    SciTech Connect

    Zaleski, R.T.; Triemer, L.R.

    1995-12-31

    Developing an exposure-effects model for plant response to ozone exposure is a complex process. It is known that ozone must enter the plant through the stomata for an effect to occur. Therefore, ozone uptake is related not only to ambient ozone concentrations, but also to environmental factors which control stomatal movement. In addition, cellular factors within the plant can mitigate ozone impact and ultimately control plant response. This paper presents a review of the scientific literature on plant responses (e.g. visible foliar injury, reductions in growth or yield) to ozone exposures under varying environmental conditions known to affect stomatal aperture. The results of this effort show the importance of considering key environmental factors when developing exposure-effects models.

  14. TOWARDS RELIABLE AND COST-EFFECTIVE OZONE EXPOSURE ASSESSMENT: PARAMETER EVALUATION AND MODEL VALIDATION USING THE HARVARD SOUTHERN CALIFORNIA CHRONIC OZONE EXPOSURE STUDY DATA

    EPA Science Inventory

    Accurate assessment of chronic human exposure to atmospheric criteria pollutants, such as ozone, is critical for understanding human health risks associated with living in environments with elevated ambient pollutant concentrations. In this study, we analyzed a data set from a...

  15. ZINC-DEFICIENCY ENHANCES PRO-INFLAMMATORY RESPONSES AFTER OZONE EXPOSURE

    EPA Science Inventory

    Epidemiological and controlled exposure studies have demonstrated that humans are differentially susceptible to adverse health effects induced by exposure to ozone. Serum analysis of vitamins and trace elements have shown that the elderly (people >65 years) are deficient in sever...

  16. Determination of oxidant exposure during ozonation of secondary effluent to predict contaminant removal.

    PubMed

    Zucker, Ines; Avisar, Dror; Mamane, Hadas; Jekel, Martin; Hübner, Uwe

    2016-09-01

    The use of kinetic models to predict oxidation performance in wastewater is limited due to fast ozone depletion during the first milliseconds of the reaction. This paper introduces the Quench Flow Module (QFM), a bench-scale experimental technique developed to measure the first 5-500 milliseconds of ozone depletion for accurate determination of ozone exposure in wastewater-ozonation processes. Calculated ozone exposure in QFM experiments was up to 24% lower than in standard batch experiments, strongly depending on the initial sampling point for measurement in batch experiments. However, oxidation rates of slowly- and moderately-reacting trace organic compounds (TrOCs) were accurately predicted from batch experiments based on integration of ozone depletion and removal of an ozone-resistant probe compound to calculate oxidant exposures. An alternative concept, where ozone and hydroxyl radical exposures are back-calculated from the removal of two probe compounds, was tested as well. Although the QFM was suggested to be an efficient mixing reactor, ozone exposure ranged over three orders of magnitude when different probe compounds reacting moderately with ozone were used for the calculation. These effects were beyond uncertainty ranges for apparent second order rate constants and consistently observed with different ozone-injection techniques, i.e. QFM, batch experiments, bubble columns and venturi injection. This indicates that previously suggested mixing effects are not responsible for the difference and other still unknown factors might be relevant. Results furthermore suggest that ozone exposure calculations from the relative residual concentration of a probe compound are not a promising option for evaluation of ozonation of secondary effluents. PMID:27232995

  17. OZONE-INDUCED RESPIRATORY SYMPTOMS AND LUNG FUNCTION DECREMENTS IN HUMANS: EXPOSURE-RESPONSE MODELS

    EPA Science Inventory

    Short duration exposure to ozone (<8 hr) is known to result in lung function decrements and respiratory symptoms in humans. The magnitudes of these responses are functions of ozone concentration (C), activity level measured by minute ventilation (Ve), duration of exposure (T), a...

  18. A DYNAMIC NONLINEAR MODEL OF OZONE-INDUCED FEV1 RESPONSE UNDER CHANGING EXPOSURE CONDITIONS

    EPA Science Inventory

    A Dynamic Nonlinear Model of Ozone-induced FEV1 Response under Changing Exposure Conditions. 1WF McDonnell, 2PW Stewart, 3MV Smith. 1Human Studies Division, NHEERL, U.S. EPA, RTP, NC. 2University of North Carolina, Chapel Hill, NC. 3ASI, Durham, NC.

    Ozone exposure result...

  19. Prolonged Exposure versus Dynamic Therapy for Adolescent PTSD: A Pilot Randomized Controlled Trial

    ERIC Educational Resources Information Center

    Gilboa-Schechtman, Eva; Foa, Edna B.; Shafran, Naama; Aderka, Idan M.; Powers, Mark B.; Rachamim, Lilach; Rosenbach, Lea; Yadin, Elna; Apter, Alan

    2010-01-01

    Objective: To examine the efficacy and maintenance of developmentally adapted prolonged exposure therapy for adolescents (PE-A) compared with active control time-limited dynamic therapy (TLDP-A) for decreasing posttraumatic and depressive symptoms in adolescent victims of single-event traumas. Method: Thirty-eight adolescents (12 to 18 years old)…

  20. Direction of Influence between Posttraumatic and Depressive Symptoms during Prolonged Exposure Therapy among Children and Adolescents

    ERIC Educational Resources Information Center

    Aderka, Idan M.; Foa, Edna B.; Applebaum, Edna; Shafran, Naama; Gilboa-Schechtman, Eva

    2011-01-01

    Objective: Our objective in the present study was to examine the temporal sequencing of posttraumatic and depressive symptoms during prolonged exposure therapy for posttraumatic stress disorder (PTSD) among children and adolescents. Method: Participants were 73 children and adolescents (56.2% female) between the ages of 8 and 18. Participants…

  1. Sudden Gains in Prolonged Exposure for Children and Adolescents with Posttraumatic Stress Disorder

    ERIC Educational Resources Information Center

    Aderka, Idan M.; Appelbaum-Namdar, Edna; Shafran, Naama; Gilboa-Schechtman, Eva

    2011-01-01

    Objective: Our objective was to examine sudden gains during developmentally adjusted prolonged exposure for posttraumatic stress disorder (PTSD) among children and adolescents. We hypothesized that sudden gains would be detected and would be predictive of treatment outcome and follow-up. Method: Sixty-three youngsters (ages 8-17) completed a…

  2. Prolonged Exposure Therapy for a Vietnam Veteran with PTSD and Early-Stage Dementia

    ERIC Educational Resources Information Center

    Duax, Jeanne M.; Waldron-Perrine, Brigid; Rauch, Sheila A. M.; Adams, Kenneth M.

    2013-01-01

    Although prolonged exposure therapy (PE) is considered an evidence-based treatment for PTSD, there has been little published about the use of this treatment for older adults with comorbid early-stage dementia. As the number of older adults in the United States continues to grow, so will their unique mental health needs. The present article…

  3. Prolonged Exposure Treatment of Chronic PTSD in Juvenile Sex Offenders: Promising Results from Two Case Studies

    ERIC Educational Resources Information Center

    Hunter, John A.

    2010-01-01

    Prolonged exposure (PE) was used to treat chronic PTSD secondary to severe developmental trauma in two adolescent male sex offenders referred for residential sex offender treatment. Both youth were treatment resistant prior to initiation of PE and showed evidence of long-standing irritability and depression/anxiety. Clinical observation and…

  4. An evaluation of ozone exposure metrics for a seasonally drought-stressed ponderosa pine ecosystem.

    PubMed

    Panek, Jeanne A; Kurpius, Meredith R; Goldstein, Allen H

    2002-01-01

    Ozone stress has become an increasingly significant factor in cases of forest decline reported throughout the world. Current metrics to estimate ozone exposure for forest trees are derived from atmospheric concentrations and assume that the forest is physiologically active at all times of the growing season. This may be inaccurate in regions with a Mediterranean climate, such as California and the Pacific Northwest, where peak physiological activity occurs early in the season to take advantage of high soil moisture and does not correspond to peak ozone concentrations. It may also misrepresent ecosystems experiencing non-average climate conditions such as drought years. We compared direct measurements of ozone flux into a ponderosa pine canopy with a suite of the most common ozone exposure metrics to determine which best correlated with actual ozone uptake by the forest. Of the metrics we assessed, SUM0 (the sum of all daytime ozone concentrations > 0) best corresponded to ozone uptake by ponderosa pine, however the correlation was only strong at times when the stomata were unconstrained by site moisture conditions. In the early growing season (May and June). SUM0 was an adequate metric for forest ozone exposure. Later in the season, when stomatal conductance was limited by drought. SUM0 overestimated ozone uptake. A better metric for seasonally drought-stressed forests would be one that incorporates forest physiological activity, either through mechanistic modeling, by weighting ozone concentrations by stomatal conductance, or by weighting concentrations by site moisture conditions. PMID:11843543

  5. Impacts of summer ozone exposure on the growth and overwintering of UK upland vegetation

    NASA Astrophysics Data System (ADS)

    Hayes, Felicity; Mills, Gina; Williams, Philip; Harmens, Harry; Büker, Patrick

    The effects of ozone exposure on species of an upland grassland were assessed. Thirty-three species from Snowdonia, North Wales, UK, were exposed for 10 weeks to a weekly episodic ozone regime in solardomes representing predicted future concentrations. Two solardomes were used as controls, with ozone added to charcoal-filtered air to give a continuous ozone concentration of 30 ppb (O 3(30)). A weekly episodic ozone regime was applied to two other solardomes, with concentrations rising for 8 h per day to 80 ppb on day 1, 100 ppb on days 2 and 3, and 80 ppb on day 4; ozone concentrations remained at 30 ppb at all other times (O 3(30+peaks)). The control and background ozone concentrations of 30 ppb were maintained throughout the night as well as during the daytime. During exposure to the episodic ozone regime, some species were sensitive to ozone and showed ozone-specific leaf injury symptoms (e.g . Carex echinata) and/or premature senescence (e.g. Festuca rubra) and/or changes in above-ground biomass (e.g. Armeria maritima), whereas other species (e.g Holcus lanatus and Carex demissa) showed no effects. Some species, although showing no effects during the 10-week ozone exposure, showed carry-over effects on biomass the following spring, after a winter period of ambient ozone exposure (e.g. Galium saxatile, Nardus stricta and Saxifraga stellaris). The carry-over effects shown in this study indicate the potential ecological impact of ozone on semi-natural vegetation species and indicate the importance of longer-term studies on the effects of ozone on plants.

  6. Suppression and recovery of the alveolar macrophage phagocytic system during continuous exposure to 0. 5 ppm ozone

    SciTech Connect

    Gilmour, M.I.; Hmieleski, R.R.; Stafford, E.A.; Jakab, G.J. )

    1991-05-01

    Short-term exposures to ozone (O3) are known to impair pulmonary antibacterial defenses and alveolar macrophage (AM) phagocytosis in a dose-related manner. To determine the effect of prolonged O3 exposure, Swiss mice were exposed continuously to 0.5 ppm O3. At 1, 3, 7, and 14 days, intrapulmonary killing was assessed by inhalation challenge with Staphylococcus aureus or Proteus mirabilis and by comparing the number of viable bacteria remaining in the lungs at 4 h between O3-exposed and control animals. To evaluate the effects of O3 on the functional capacity of the AMs, Fc-receptor mediated phagocytosis was assessed. Ozone exposure impaired the intrapulmonary killing of S. aureus at 1 and 3 days; however, with prolonged exposure, the bactericidal capacity of the lungs returned to normal. This trend of an initial suppression followed by recovery was reflected in the phagocytic capacity of the AMs. In contrast to S. aureus, when P. mirabilis was used as the challenge organism, O3 exposure had no suppressive effect on pulmonary bactericidal activity, which correlated with an increase in the phagocytic cell population in the lungs. Morphologic examination of the lavaged macrophages showed that after 1 day of O3 exposure, the AMs were more foamy, and contained significantly more vacuoles. There was also a significant increase in binucleated cells at 3 days. These studies demonstrate that continuous exposure to O3 modulates AM-dependent lung defenses and points to the importance of the challenge organism and exposure protocol in establishing the adverse effect of O3.

  7. Chlorophyll fluorescence quenching during ozone exposure of leaves of Phaseolus vulgaris (pinto)

    SciTech Connect

    Guralnick, L.J. ); Miller, R.; Heath, R.L. )

    1990-05-01

    During ozone exposure, observations have noted an initial decrease in CO{sub 2} uptake followed by a decrease in stomatal conductance. We examined this response utilizing the technique of fluorescence quenching. Fourteen day old plants were exposed to 0.3 ul/l ozone for 1 hour. Fluorescence quenching was monitored using the Hanstech modulated fluorescence system. This enabled us to measure changes in photochemical quenching (qQ) and non-photochemical quenching (qE) in control and ozone treated plants. Results have indicated no differences in qQ and qE between ozone treated and control plants. We are initiating further studies utilizing different ozone levels.

  8. Effect of controlled ozone exposure on human lymphocyte function

    SciTech Connect

    Peterson, M.L.; Smialowicz, R.; Harder, S.; Ketcham, B.; House, D.

    1981-04-01

    The effects of ozone (O/sub 3/) on cell-mediated immunity were studied in 16 human subjects exposed to 1176 ..mu..g/m/sup 3/ O/sub 3/ (0.6 ppM) for 2 h in an environmentally controlled exposure chamber. Venous blood samples were taken before and immediately after controlled air and O/sub 3/ exposures, as well as at 72 h, 2 and 4 weeks, and at one random time at least 1 month after treatment. The relative frequency of T lymphocytes in blood and the in vitro blastogenic response of lymphocytes to phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM), and Candida albicans were determined. During the course of the experiment, no statistically significant changes were observed in the number of T lymphocytes that form spontaneous rosettes with sheep erythrocytes. The response of T lymphocytes to PHA was significantly reduced (P < 0.05) in samples taken at 2 and 4 weeks, following O/sub 3/ exposure. Normal response to PHA was observed at 2 months post-O/sub 3/ exposure. No statistically significant changes in lymphocyte responses to Con A, PWM, or Candida were seen. These results show that one 2 h exposure of humans to 0.6 ppM O/sub 3/ may lead to a transient suppression of the PHA-stimulated blastogenic transformation of peripheral blood lymphocytes. The data indicate that the blastogenic response to PHA of human lymphocytes is exquisitely sensitive to O/sub 3/ exposure and could serve as a bioassay for evaluating subtle changes in cellular immunity induced by O/sub 3/ and possibly other pollutants.

  9. Physiological Stress Responses to Prolonged Exposure to MS-222 and Surgical Implantation in Juvenile Chinook Salmon

    SciTech Connect

    Wagner, Katie A.; Woodley, Christa M.; Seaburg, Adam; Skalski, John R.; Eppard, Matthew B.

    2014-07-17

    While many studies have investigated the effects of transmitters on fish condition, behavior, and survival, to our knowledge, no studies have taken into account anesthetic exposure time in addition to tag and surgery effects. We investigated stress responses to prolonged MS-222 exposure after stage 4 induction in surgically implanted juvenile Chinook salmon (Oncorhynchus tshawytscha). Survival, tag loss, plasma cortisol concentration, and blood Na+, K+, Ca2+, and pH were measured immediately following anesthetic exposure and surgical implantation and 1, 7, and 14 days post-treatment. Despite the prolonged anesthetic exposure, 3-15 minutes post Stage 4 induction, there were no mortalities or tag loss in any treatment. MS-222 was effective at delaying immediate cortisol release during surgical implantation; however, osmotic disturbances resulted, which were more pronounced in longer anesthetic time exposures. From day 1 to day 14, Na+, Ca2+, and pH significantly decreased, while cortisol significantly increased. The cortisol increase was exacerbated by surgical implantation. There was a significant interaction between MS-222 time exposure and observation day for Na+, Ca2+, K+, and pH; variations were seen in the longer time exposures, although not consistently. In conclusion, stress response patterns suggest stress associated with surgical implantation is amplified with increased exposure to MS-222.

  10. Systemic metabolic derangement, pulmonary effects, and insulin insufficiency following subchronic ozone exposure in rats.

    PubMed

    Miller, Desinia B; Snow, Samantha J; Henriquez, Andres; Schladweiler, Mette C; Ledbetter, Allen D; Richards, Judy E; Andrews, Debora L; Kodavanti, Urmila P

    2016-09-01

    Acute ozone exposure induces a classical stress response with elevated circulating stress hormones along with changes in glucose, protein and lipid metabolism in rats, with similar alterations in ozone-exposed humans. These stress-mediated changes over time have been linked to insulin resistance. We hypothesized that acute ozone-induced stress response and metabolic impairment would persist during subchronic episodic exposure and induce peripheral insulin resistance. Male Wistar Kyoto rats were exposed to air or 0.25ppm or 1.00ppm ozone, 5h/day, 3 consecutive days/week (wk) for 13wks. Pulmonary, metabolic, insulin signaling and stress endpoints were determined immediately after 13wk or following a 1wk recovery period (13wk+1wk recovery). We show that episodic ozone exposure is associated with persistent pulmonary injury and inflammation, fasting hyperglycemia, glucose intolerance, as well as, elevated circulating adrenaline and cholesterol when measured at 13wk, however, these responses were largely reversible following a 1wk recovery. Moreover, the increases noted acutely after ozone exposure in non-esterified fatty acids and branched chain amino acid levels were not apparent following a subchronic exposure. Neither peripheral or tissue specific insulin resistance nor increased hepatic gluconeogenesis were present after subchronic ozone exposure. Instead, long-term ozone exposure lowered circulating insulin and severely impaired glucose-stimulated beta-cell insulin secretion. Thus, our findings in young-adult rats provide potential insights into epidemiological studies that show a positive association between ozone exposures and type 1 diabetes. Ozone-induced beta-cell dysfunction may secondarily contribute to other tissue-specific metabolic alterations following chronic exposure due to impaired regulation of glucose, lipid, and protein metabolism. PMID:27368153

  11. Microscopic changes in Avena and Phaseolus from ozone exposure

    SciTech Connect

    Evans, L.S.

    1985-01-01

    Seedlings of Avena and Phaseolus were exposed to 0.30 ppM ozone for up to 5 hr. Histological and histochemical observations indicated injuries occurred as early after exposure as 1/4 hr in beans and 1/2 hr in oats. Both species exhibited similar symptoms on a cellular level. Symptoms include a less orderly arrangement within and among chloroplasts and the ultimate amorphous aggregation of chloroplasts adjacent to the plasmalemma. Folding and fracturing of the plasmalemma and cell walls occurred in many thin walled cells. This latter symptom was less obvious in thick-walled cells. Symptoms are described at 1/4 hr intervals for the first 3 hr during fumigation. 16 references, 6 figures.

  12. Use of AIRS, OMI, MLS, and TES Data in Assessing Forest Ecosystem Exposure to Ozone

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.

    2007-01-01

    Ground-level ozone at high levels poses health threats to exposed flora and fauna, including negative impacts to human health. While concern is common regarding depletion of ozone in the stratosphere, portions of the urban and rural United States periodically have high ambient levels of tropospheric ozone on the ground. Ozone pollution can cause a variety of impacts to susceptible vegetation (e.g., Ponderosa and Jeffrey pine species in the southwestern United States), such as stunted growth, alteration of growth form, needle or leaf chlorosis, and impaired ability to withstand drought-induced water stress. In addition, Southern Californian forests with high ozone exposures have been recently subject to multiyear droughts that have led to extensive forest overstory mortality from insect outbreaks and increased incidence of wildfires. Residual forests in these impacted areas may be more vulnerable to high ozone exposures and to other forest threats than ever before. NASA sensors collect a wealth of atmospheric data that have been used recently for mapping and monitoring regional tropospheric ozone levels. AIRS (Atmospheric Infrared Sounder), OMI (Ozone Monitoring Instrument), MLS (Microwave Limb Sounder), and TES (Tropospheric Emission Spectrometer) data could be used to assess forest ecosystem exposure to ozone. Such NASA data hold promise for providing better or at least complementary synoptic information on ground-level ozone levels that Federal agency partners can use to assess forest health trends and to mitigate the threats as needed in compliance with Federal laws and mandates. NASA data products on ozone concentrations may be able to aid applications of DSTs (decision support tools) adopted by the USDA FS (U.S. Department of Agriculture Forest Service) and by the NPS (National Park Service), such as the Ozone Calculator, in which ground ozone estimates are employed to assess ozone impacts to forested vegetation.

  13. [UV exposure, skin cancer and decrease in the ozone layer].

    PubMed

    Rauterberg, A; Jung, E G

    1993-12-01

    All over the world a remarkable increase in malignant tumors of the skin is reported. More than 90% of them are localized in areas of the skin exposed to sunlight. The incidence of malignant melanomas of the skin is tenfold higher today than 40 years ago. Experimental data and results of epidemiological studies indicate two different risk patterns of UV exposure for the development of skin cancer. The cumulative UV-light exposure during lifetime induces--especially in light-sensitive individuals older than 60 years--actinic elastosis, precanceroses and squamous cell carcinomas as well as lentigo maligna melanomas. Intense UV exposure in childhood and youth may lead to development of superficial spreading melanomas and nodular melanomas between the age of 20 and 40. The reduction of ozone in the stratosphere could still contribute to a higher incidence of tumors of the skin in the next decades. The evident role of UVB light in the induction of tumors of the skin offers the possibility for preventive strategies.

  14. Ozone influence on native vegetation in the Jizerske hory Mts. of the Czech Republic: results based on ozone exposure and ozone-induced visible symptoms.

    PubMed

    Hůnová, Iva; Matoušková, Leona; Srněnský, Radek; Koželková, Klára

    2011-12-01

    Ozone levels in the Jizerske hory Mts. measured at 13 sites by diffusive samplers during the 2006 and 2007 vegetation seasons are presented. A significant ozone gradient (5.4 ppb in 2006 and 4.0 ppb in 2007) per 100 m difference in altitude between 370 and 1,100 m a.s.l. was recorded. High-resolution maps of phytotoxic potential were developed. The AOT40 threshold (5 ppm h) was exceeded over the entire area with the highest levels exceeding this threshold by 12 times in the upper portions of the mountains. Ozone visible injury was evaluated at four of the monitoring sites on seven native plant and tree species. Four species showed ozone-like symptoms, two of which (Rubus idaeus and Fagus sylvatica) were confirmed as ozone-induced. Our results indicate that ambient ozone is likely to have a much lower impact on the Jizerske hory Mts. vegetation than expected, considering the measured ambient ozone exposures and favourable environmental conditions for ozone uptake.

  15. Pulmonary function and symptom responses after 6. 6-hour exposure to 0. 12-ppm ozone with moderate exercise (journal version)

    SciTech Connect

    Folinsbee, L.J.; Horstman, D.H.; McDonnell, W.F.

    1988-01-01

    Episodes occasionally occur when ambient ozone (O/sub 3/) levels remain at or near 0.12 ppm for more than 6 h. The hypothesis that prolonged exposure to 0.12 ppm O/sub 3/ would result in progressively larger changes in respiratory function and symptoms over time was tested. Ten nonsmoking males (18-35 yr) were exposed once to clear air (CA) and once to 0.12 pp, O/sub 3/ for 6.75 h. Exposures consisted of six 50-min exercise periods, each followed by 10-min rest and measurement; a 45-min lunch period followed the third exercise period. Exercise ventilation averaged approximately 40 1/min. Forced expiratory and inspiratory spirometry and respiratory symptoms were measured prior to exposure and after each exercise. Increases in the symptom ratings of cough and pain on deep inspiration were observed with O/sub 3/ exposure but not with CA. Airway reactivity to methacholine was approximately doubled following O/sub 3/ exposure. Spirometry results indicate that prolonged exposure to 0.12 ppm O/sub 3/ results in a marked increase in non-specific airway reactivity and progressive changes in respiratory function.

  16. Diel trend in plant sensitivity to ozone: Implications for exposure- and flux-based ozone metrics

    NASA Astrophysics Data System (ADS)

    Grantz, David A.

    2014-12-01

    Plant sensitivity to ozone (O3) is critical to modeling impacts of air pollution on vegetation. A diel timecourse of sensitivity (S) was recently determined in Pima cotton (Grantz et al., 2013). The sensitivity parameter serves as a weighting factor for stomatal uptake (ozone flux, F), or cumulative F (dose, D). Previous approaches used various weighting schemes to modify ozone concentration ([O3]) or cumulative [O3] (exposure, E). Use of the S parameter allows calculation of effective flux (Feff) and effective dose (Deff). Though theoretically sound, the practical significance of S has not been evaluated due to the previous lack of available data. Here, the newly available S parameter is used to explore the relationships between exposure- and flux-based O3 metrics in response to scenarios of contrasting stomatal conductance (gs) and ambient [O3]. The O3 scenarios were similar but differed in timing of peak [O3]. E varied by up to 13.7%, D by up to 15.4%, and Deff, which factors in sensitivity, by up to 19.0%. The gs scenarios differed in midday magnitude and nocturnal closure. Cumulative gs varied by 65.2%, which was attenuated in D to 49.2% and in Deff to 51.1%. A simulation of hourly [O3], F, and Feff was run using Monte Carlo techniques with a full month of ambient [O3] data. Resulting diel timecourses of [O3], F, and Feff were realistic, with the principal sources of uncertainty in the physiological parameters, gs and S. Analysis of hourly values from the scenarios and the simulation output demonstrated significant correlation among the O3 metrics. However, the uncertainty in both F and Feff predicted from [O3] was large and proportional to [O3], yielding greatest uncertainty under conditions of high [O3] and potential phytotoxicity. In contrast, Feff was significantly correlated with F, with low variability that was not proportional to F. As a result, uncertainty was low and prediction potentially useful under conditions of likely injury. These results

  17. Effects of ozone and acid aerosol exposures on surfactant-associated protein A in the lung

    SciTech Connect

    Su, W.Y.

    1993-01-01

    This study examined the effect of ozone and/or acid aerosol exposure on the level of surfactant associated protein A (SP-A), its gene expression and functionality in the lung. Guinea pigs were exposed to (1) a single exposure to 0.2 to 0.8 ppm ozone for 6 hr and sacrificed at 0 to 120 hr postexposure, (2) 0.8 ppm ozone, 6 hr/day for 3 to 5 days and sacrificed immediately postexposure, or (3) 0.8 ppm ozone, 600 [mu]g/m[sup 3] sulfuric acid, or ozone plus acid for 6 hr and sacrificed at 72 hr postexposure. The concentration of SP-A was determined by ELISA in lavage fluid, lavage cell pellets, and lung tissue compartments. SP-A gene expression was examined in lung tissue by Northern and slot blot analysis. Effect of ozone exposure on functionality of surfactant was tested by its ability to modulate phagocytic cell respiratory burst in a luminol-amplified chemiluminescence (CL) assay of phagocytic cells simulated by PMA or opsonized-zymosan. There were isolated, but significant, changes in SP-A concentrations in the lavage cell and the lavage fluid compartments at 24 and 48 hr after single exposure to 0.8 ppm ozone, respectively. Exposure to ozone and ozone plus acid also slightly increased total SP-A level in the lung. No change in SP-A gene expression was detected under the exposure conditions examined. However, surfactant from ozone exposed animals significantly enhanced CL response of phagocytic cells stimulated by either PMA or opsonized-zymosan. Blocking of the enhancement of CL by a rabbit anti-human SP-A antibody strongly suggested that SP-A may contribute in the altered respiratory burst of phagocytic cells induced by surfactant from ozone exposed animals.

  18. Prolonged exposure to insulin induces mitochondrion-derived oxidative stress through increasing mitochondrial cholesterol content in hepatocytes.

    PubMed

    Mei, Shuang; Gu, Haihua; Yang, Xuefeng; Guo, Huailan; Liu, Zhenqi; Cao, Wenhong

    2012-05-01

    We addressed the link between excessive exposure to insulin and mitochondrion-derived oxidative stress in this study and found that prolonged exposure to insulin increased mitochondrial cholesterol in cultured hepatocytes and in mice and stimulated production of reactive oxygen species (ROS) and decreased the reduced glutathione to glutathione disulfide ratio in cultured hepatocytes. Exposure of isolated hepatic mitochondria to cholesterol alone promoted ROS emission. The oxidative stress induced by the prolonged exposure to insulin was prevented by inhibition of cholesterol synthesis with simvastatin. We further found that prolonged exposure to insulin decreased mitochondrial membrane potential and the increased ROS production came from mitochondrial respiration complex I. Finally, we observed that prolonged exposure to insulin decreased mitochondrial membrane fluidity in a cholesterol synthesis-dependent manner. Together our results demonstrate that excess exposure to insulin causes mitochondrion-derived oxidative stress through cholesterol synthesis in hepatocytes.

  19. Does ozone exposure alter growth and carbon allocation of mycorrhizal plants

    SciTech Connect

    Yoshida, L.C.; Gamon, J.A. ); Andersen, C.P. )

    1994-06-01

    Ozone is known to adversely affect plant growth. However, it is less clear how ozone affects belowground processes. This study tests the hypothesis that ozone alters growth and carbon allocation of vesicular arbuscular mycorrhizal (VAM) plants. Two ecotypes of Elymus glaucus (blue wild rye) were exposed to mycorrhizal inoculation and episodic ozone exposures simulating atmospheric conditions in the Los Angeles Basin. Preliminary results show that effects of ozone on growth were subtle. In both ecotypes, growth of aboveground biomass was not affected by ozone while root growth was decreased. In most treatments, mycorrhizal inoculation decreased growth of leaves and stems, but had no significant effect on root growth. Three-way ANOVA tests indicated interactive effects between ecotype, mycorrhiza and ozone. Further experimental work is needed to reveal the biological processes governing these responses.

  20. Effects of prolonged exposure to space flight factors for 175 days on lettuce seeds

    NASA Astrophysics Data System (ADS)

    Nevzgodina, L. V.; Maximova, E. N.; Akatov, Yu. A.

    We have studied the effects of prolonged (up to 175 days) exposure of Lactuca sativa seeds to space flight factors, including primary cosmic radiation heavy ions. The data obtained evidence a significant fourfold increase ofs pontaneous mutagenesis in seeds both with regard to the total number of aberrant cells as well as the formation of single cells with multiple aberrations. Comparison of the present experiment with earlier works shows that the frequency of such aberrations increases with the duration of the flight.

  1. Effects of prolonged exposure to space flight factors for 175 days on lettuce seeds

    SciTech Connect

    Nevzgodina, L.V.; Maximova, E.N.; Akatov, Yu.A.

    1981-01-01

    The effects of prolonged (up to 175 days) exposure of Lactuca sativa seeds to space flight factors, including primary cosmic radiation heavy ions have been studied. The data obtained evidence a significant fourfold increase of spontaneous mutagenesis in seeds both with regard to the total number of aberrant cells as well as the formation of single cells with multiple aberrations. Comparison of the present experiment with earlier works shows that the frequency of such aberrations increases with the duration of the flight.

  2. Ozone pollution and ozone biomonitoring in European cities. Part I: Ozone concentrations and cumulative exposure indices at urban and suburban sites

    NASA Astrophysics Data System (ADS)

    Klumpp, Andreas; Ansel, Wolfgang; Klumpp, Gabriele; Calatayud, Vicent; Pierre Garrec, Jean; He, Shang; Peñuelas, Josep; Ribas, Àngela; Ro-Poulsen, Helge; Rasmussen, Stine; Sanz, María José; Vergne, Phillippe

    In the frame of a European research project on air quality in urban agglomerations, data on ozone concentrations from 23 automated urban and suburban monitoring stations in 11 cities from seven countries were analysed and evaluated. Daily and summer mean and maximum concentrations were computed based on hourly mean values, and cumulative ozone exposure indices ( Accumulated exposure Over a Threshold of 40 ppb (AOT40), AOT20) were calculated. The diurnal profiles showed a characteristic pattern in most city centres, with minimum values in the early morning hours, a strong rise during the morning, peak concentrations in the afternoon, and a decline during the night. The widest amplitudes between minimum and maximum values were found in central and southern European cities such as Düsseldorf, Verona, Klagenfurt, Lyon or Barcelona. In the northern European cities of Edinburgh and Copenhagen, by contrast, maximum values were lower and diurnal variation was much smaller. Based on ozone concentrations as well as on cumulative exposure indices, a clear north-south gradient in ozone pollution, with increasing levels from northern and northwestern sites to central and southern European sites, was observed. Only the Spanish cities did not fit this pattern; there, ozone levels were again lower than in central European cities, probably due to the direct influence of strong car traffic emissions. In general, ozone concentrations and cumulative exposure were significantly higher at suburban sites than at urban and traffic-exposed sites. When applying the newly established European Union (EU) Directive on ozone pollution in ambient air, it was demonstrated that the target value for the protection of human health was regularly surpassed at urban as well as suburban sites, particularly in cities in Austria, France, northern Italy and southern Germany. European target values and long-term objectives for the protection of vegetation expressed as AOT40 were also exceeded at many

  3. Systemic Metabolic Derangement, Pulmonary Effects, and Insulin Insufficiency following subchronic ozone exposure in rats

    EPA Science Inventory

    Acute ozone exposure induces a classical stress response with elevated circulating stress hormones along with changes in glucose, protein and lipid metabolism in rats, with similar alterations in ozone-exposed humans. These stress-mediated changes over time have been linked to in...

  4. AN EVALUATION OF OZONE EXPOSURE METRICS FOR A SEASONALLY DROUGHT STRESSED PONDEROSA PINE ECOSYSTEM. (R826601)

    EPA Science Inventory

    Ozone stress has become an increasingly significant factor in cases of forest decline reported throughout the world. Current metrics to estimate ozone exposure for forest trees are derived from atmospheric concentrations and assume that the forest is physiologically active at ...

  5. Low level ozone exposure induces airways inflammation and modifies cell surface phenotypes in healthy humans

    EPA Science Inventory

    Background: The effects of low level ozone exposure (0.08 ppm) on pulmonary function in healthy young adults are well known, however much less is known about the inflammatory and immuno-modulatory effects oflow level ozone in the airways. Techniques such as induced sputum and flo...

  6. Long-Term Exposure to Ozone and Life Expectancy in the United States, 2002 to 2008.

    PubMed

    Li, Chaoyang; Balluz, Lina S; Vaidyanathan, Ambarish; Wen, Xiao-Jun; Hao, Yongping; Qualters, Judith R

    2016-02-01

    Long-term exposure to ground-level ozone is associated with increased risk of morbidity and mortality. The association remains uncertain between long-term exposure to ozone and life expectancy. We assessed the associations between seasonal mean daily 8-hour maximum (8-hr max) ozone concentrations measured during the ozone monitoring seasons and life expectancy at birth in 3109 counties of the conterminous U.S. during 2002 to 2008. We used latent class growth analysis to identify latent classes of counties that had distinct mean levels and rates of change in ozone concentrations over the 7-year period and used linear regression analysis to determine differences in life expectancy by ozone levels. We identified 3 classes of counties with distinct seasonal mean daily 8-hr max ozone concentrations and rates of change. When compared with the counties with the lowest ozone concentrations, the counties with the highest ozone concentrations had 1.7- and 1.4-year lower mean life expectancy in males and females (both P < 0.0001), respectively. The associations remained statistically significant after controlling for potential confounding effects of seasonal mean PM2.5 concentrations and other selected environmental, demographic, socio-economic, and health-related factors (both P < 0.0001). A 5 ppb higher ozone concentration was associated with 0.25 year lower life expectancy in males (95% CI: -0.30 to -0.19) and 0.21 year in females (95% CI: -0.25 to -0.17). We identified 3 classes of counties with distinct mean levels and rates of change in ozone concentrations. Our findings suggest that long-term exposure to a higher ozone concentration may be associated with a lower life expectancy.

  7. Long-Term Exposure to Ozone and Life Expectancy in the United States, 2002 to 2008

    PubMed Central

    Li, Chaoyang; Balluz, Lina S.; Vaidyanathan, Ambarish; Wen, Xiao-Jun; Hao, Yongping; Qualters, Judith R.

    2016-01-01

    Abstract Long-term exposure to ground-level ozone is associated with increased risk of morbidity and mortality. The association remains uncertain between long-term exposure to ozone and life expectancy. We assessed the associations between seasonal mean daily 8-hour maximum (8-hr max) ozone concentrations measured during the ozone monitoring seasons and life expectancy at birth in 3109 counties of the conterminous U.S. during 2002 to 2008. We used latent class growth analysis to identify latent classes of counties that had distinct mean levels and rates of change in ozone concentrations over the 7-year period and used linear regression analysis to determine differences in life expectancy by ozone levels. We identified 3 classes of counties with distinct seasonal mean daily 8-hr max ozone concentrations and rates of change. When compared with the counties with the lowest ozone concentrations, the counties with the highest ozone concentrations had 1.7- and 1.4-year lower mean life expectancy in males and females (both P < 0.0001), respectively. The associations remained statistically significant after controlling for potential confounding effects of seasonal mean PM2.5 concentrations and other selected environmental, demographic, socio-economic, and health-related factors (both P < 0.0001). A 5 ppb higher ozone concentration was associated with 0.25 year lower life expectancy in males (95% CI: −0.30 to −0.19) and 0.21 year in females (95% CI: −0.25 to −0.17). We identified 3 classes of counties with distinct mean levels and rates of change in ozone concentrations. Our findings suggest that long-term exposure to a higher ozone concentration may be associated with a lower life expectancy. PMID:26886595

  8. Long-Term Exposure to Ozone and Life Expectancy in the United States, 2002 to 2008.

    PubMed

    Li, Chaoyang; Balluz, Lina S; Vaidyanathan, Ambarish; Wen, Xiao-Jun; Hao, Yongping; Qualters, Judith R

    2016-02-01

    Long-term exposure to ground-level ozone is associated with increased risk of morbidity and mortality. The association remains uncertain between long-term exposure to ozone and life expectancy. We assessed the associations between seasonal mean daily 8-hour maximum (8-hr max) ozone concentrations measured during the ozone monitoring seasons and life expectancy at birth in 3109 counties of the conterminous U.S. during 2002 to 2008. We used latent class growth analysis to identify latent classes of counties that had distinct mean levels and rates of change in ozone concentrations over the 7-year period and used linear regression analysis to determine differences in life expectancy by ozone levels. We identified 3 classes of counties with distinct seasonal mean daily 8-hr max ozone concentrations and rates of change. When compared with the counties with the lowest ozone concentrations, the counties with the highest ozone concentrations had 1.7- and 1.4-year lower mean life expectancy in males and females (both P < 0.0001), respectively. The associations remained statistically significant after controlling for potential confounding effects of seasonal mean PM2.5 concentrations and other selected environmental, demographic, socio-economic, and health-related factors (both P < 0.0001). A 5 ppb higher ozone concentration was associated with 0.25 year lower life expectancy in males (95% CI: -0.30 to -0.19) and 0.21 year in females (95% CI: -0.25 to -0.17). We identified 3 classes of counties with distinct mean levels and rates of change in ozone concentrations. Our findings suggest that long-term exposure to a higher ozone concentration may be associated with a lower life expectancy. PMID:26886595

  9. Controlled Exposure of Healthy Young Volunteers to Ozone Causes Cardiovascular Effects

    EPA Science Inventory

    Background: Recent epidemiology studies have reported associations between acute ozone exposure and mortality. Such studies have previously reported associations between airborne particulate matter pollution (PM) and mortality and support for a causal relationship has come from c...

  10. Controlled exposure of healthy young volunteers to ozone causes cardiovascular effects**

    EPA Science Inventory

    Background: Recent epidemiology studies have reported associations between acute ozone exposure and mortality. Such studies have previously reported associations between airborne particulate matter pollution (PM) and mortality and support for a causal relationship has come from c...

  11. Germination of fungal conidia after exposure to low concentration ozone atmospheres.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The germinability of conidia of Alternaria alternata, Aspergillus flavus, Aspergillus niger, Penicillium digitatum, Penicillium expansum, or Penicillium italicum was determined periodically during exposure for approximately 100 days to a humid atmosphere of air alone or air containing 150 ppb ozone ...

  12. Ozone Exposure Increases Circulating Stress Hormones and Lipid Metabolites in Humans

    EPA Science Inventory

    RATIONALE: Air pollution has been associated with increased prevalence of type 2 diabetes; however, the mechanisms remain unknown. We have shown that acute ozone exposure in rats induces release of stress hormones, hyperglycemia, leptinemia, and gluoose intolerance that are assoc...

  13. Relationship of ozone exposure and leaf ontogeny to susceptibility of eastern cottonwood to four pests

    SciTech Connect

    Coleman, J.S.

    1987-01-01

    The aim of this research was to determine if ozone exposure would alter the susceptibility of eastern cottonwood (Populus deltoides Bartr.) to four common pests (biotic stresses) which exploit leaf resources in different ways. Two clones of P. deltoides were exposed to 0.20 ppm ozone, or charcoal-filtered air, for five hours in greenhouse or field exposure chambers. Forty hours after ozone exposure, leaf material was exposed to Melampsora medusae Thum. (biotrophic rust fungus), Marssonina brunnea (Ell. and Ev.) P. Magn. (necrotrophic fungus), Plagiodera versicolora Laich. (chewing insect) or Chaitophorus populicola Thomas (sucking insect) in a series of leaf disk, intact leaf, or whole-plant bioassays. Plant growth parameters were also measured before and after exposure. The ozone dose did not result in changes of plant growth, or in the production of foliar lesions on any leaves which were bioassayed.

  14. Home cage locomotor changes in non-human primates after prolonged welding-fume exposure.

    PubMed

    Kim, Choong Yong; Sung, Jae Hyuck; Chung, Yong Hyun; Park, Jung Duck; Han, Jeong Hee; Lee, Jong Seong; Heo, Jeong Doo; Yu, Il Je

    2013-12-01

    To define the relationship between the brain concentration of manganese and neurological signs, such as locomotion, after prolonged welding-fume exposure, cynomolgus monkeys were acclimated for 1 month and then divided into three concentration groups: unexposed, low concentration (31 mg/m(3) total suspended particulate (TSP), 0.9 mg/m(3) of Mn), and high concentration (62 mg/m(3) TSP, 1.95 mg/m(3) of Mn) of TSP. The monkeys were exposed to manual metal-arc stainless steel (MMA-SS) welding fumes for 2 h per day over 8 months in an inhalation chamber system equipped with an automatic fume generator. The home cage locomotor activity and patterns were determined using a camera system over 2-4 consecutive days. After 25 and 32 weeks of exposure, the home cage locomotor activity of the high-concentration primates was found to be 5-6 times higher than that of the unexposed primates, and this increased locomotor activity was maintained for 7 weeks after ceasing the welding-fume exposure, eventually subsiding to three times higher after 13 weeks of recovery. Therefore, the present results, along with our previous observations of a high magnetic resonance imaging (MRI) T1 signal in the globus pallidus and increased blood Mn concentration, indicate that prolonged welding-fume exposure can cause neurobehavioral changes in cynomolgus monkeys. PMID:24304306

  15. Home cage locomotor changes in non-human primates after prolonged welding-fume exposure.

    PubMed

    Kim, Choong Yong; Sung, Jae Hyuck; Chung, Yong Hyun; Park, Jung Duck; Han, Jeong Hee; Lee, Jong Seong; Heo, Jeong Doo; Yu, Il Je

    2013-12-01

    To define the relationship between the brain concentration of manganese and neurological signs, such as locomotion, after prolonged welding-fume exposure, cynomolgus monkeys were acclimated for 1 month and then divided into three concentration groups: unexposed, low concentration (31 mg/m(3) total suspended particulate (TSP), 0.9 mg/m(3) of Mn), and high concentration (62 mg/m(3) TSP, 1.95 mg/m(3) of Mn) of TSP. The monkeys were exposed to manual metal-arc stainless steel (MMA-SS) welding fumes for 2 h per day over 8 months in an inhalation chamber system equipped with an automatic fume generator. The home cage locomotor activity and patterns were determined using a camera system over 2-4 consecutive days. After 25 and 32 weeks of exposure, the home cage locomotor activity of the high-concentration primates was found to be 5-6 times higher than that of the unexposed primates, and this increased locomotor activity was maintained for 7 weeks after ceasing the welding-fume exposure, eventually subsiding to three times higher after 13 weeks of recovery. Therefore, the present results, along with our previous observations of a high magnetic resonance imaging (MRI) T1 signal in the globus pallidus and increased blood Mn concentration, indicate that prolonged welding-fume exposure can cause neurobehavioral changes in cynomolgus monkeys.

  16. Prolonged exposure and virtual reality-enhanced imaginal exposure for PTSD following a terrorist bulldozer attack: a case study.

    PubMed

    Freedman, Sara A; Hoffman, Hunter G; Garcia-Palacios, Azucena; Tamar Weiss, Patrice L; Avitzour, Sara; Josman, Naomi

    2010-02-01

    In this case study, virtual reality was used to augment imaginal exposure in a protocol based on prolonged exposure. A 29-year-old male patient developed posttraumatic stress disorder after surviving a deadly terrorist bulldozer attack on two civilian buses and several cars in Jerusalem; the traumas witnessed by the survivor included a decapitation. The crowded bus in which the patient was riding was pushed over onto its side by the terrorist, injuring, trapping, and terrifying the passengers and causing gasoline to leak. Guided by his therapist, the patient entered an immersive computer-generated virtual world to go "back" to the scene of the traumatic event to help him gain access to his memories of the event, process and reduce the intensity of the emotions (fear/anger) associated with his pathological memories, and change unhealthy thought patterns. Traumatic memories of childhood abuse and traumatic memories of the bulldozer terrorist attack were treated using imaginal exposure while the patient was in the virtual environment BusWorld. The patient showed large posttreatment reductions in PTSD symptoms, and his Clinician-Administered PTSD Scale (CAPS) scores dropped from 79 pretreatment to zero immediately posttreatment, and CAPS was still at zero 6 months later. Although case studies are inconclusive by nature, these encouraging preliminary results suggest that further exploration of the use of virtual reality during modified prolonged exposure for PTSD is warranted. As terrorist attacks increase in frequency and severity worldwide, research is needed on how to minimize the psychological consequences of terrorism.

  17. Short and prolonged exposure to hyperglycaemia in human fibroblasts and endothelial cells: metabolic and osmotic effects.

    PubMed

    Moruzzi, Noah; Del Sole, Marianna; Fato, Romana; Gerdes, Jantje M; Berggren, Per-Olof; Bergamini, Christian; Brismar, Kerstin

    2014-08-01

    High blood glucose levels are the main feature of diabetes. However, the underlying mechanism linking high glucose concentration to diabetic complications is still not fully elucidated, particularly with regard to human physiology. Excess of glucose is likely to trigger a metabolic response depending on the cell features, activating deleterious pathways involved in the complications of diabetes. In this study, we aim to elucidate how acute and prolonged hyperglycaemia alters the biology and metabolism in human fibroblasts and endothelial cells. We found that hyperglycaemia triggers a metabolic switch from oxidative phosphorylation to glycolysis that is maintained over prolonged time. Moreover, osmotic pressure is a major factor in the early metabolic response, decreasing both mitochondrial transmembrane potential and cellular proliferation. After prolonged exposure to hyperglycaemia we observed decreased mitochondrial steady-state and uncoupled respiration, together with a reduced ATP/ADP ratio. At the same time, we could not detect major changes in mitochondrial transmembrane potential and reactive oxygen species. We suggest that the physiological and metabolic alterations observed in healthy human primary fibroblasts and endothelial cells are an adaptive response to hyperglycaemia. The severity of metabolic and bioenergetics impairment associated with diabetic complications may occur after longer glucose exposure or due to interactions with cell types more sensitive to hyperglycaemia.

  18. Transcriptome Profiling of the Newborn Mouse Lung Response to Acute Ozone Exposure

    PubMed Central

    Loader, Joan E.; White, Carl W.; Dakhama, Azzeddine

    2014-01-01

    Ozone pollution is associated with adverse effects on respiratory health in adults and children but its effects on the neonatal lung remain unknown. This study was carried out to define the effect of acute ozone exposure on the neonatal lung and to profile the transcriptome response. Newborn mice were exposed to ozone or filtered air for 3h. Total RNA was isolated from lung tissues at 6 and 24h after exposure and was subjected to microarray gene expression analysis. Compared to filtered air-exposed littermates, ozone-exposed newborn mice developed a small but significant neutrophilic airway response associated with increased CXCL1 and CXCL5 expression in the lung. Transcriptome analysis indicated that 455 genes were down-regulated and 166 genes were up-regulated by at least 1.5-fold at 6h post-ozone exposure (t-test, p < .05). At 24h, 543 genes were down-regulated and 323 genes were up-regulated in the lungs of ozone-exposed, compared to filtered air-exposed, newborn mice (t-test, p < .05). After controlling for false discovery rate, 50 genes were identified as significantly down-regulated and only a few (RORC, GRP, VREB3, and CYP2B6) were up-regulated at 24h post-ozone exposure (q < .05). Gene ontology enrichment analysis revealed that cell cycle-associated functions including cell division/proliferation were the most impacted pathways, which were negatively regulated by ozone exposure, an adverse effect that was associated with reduced bromo-deoxyuridine incorporation. These results demonstrate that acute ozone exposure alters cell proliferation in the developing neonatal lung through a global suppression of cell cycle function. PMID:24336422

  19. Monitoring of Occupational Exposure of Mild Steel Welders to Ozone and Nitrogen Oxides

    PubMed Central

    Esmaeilzadeh, Morteza; Mehrabi, Yadollah; Salehpour, Sousan

    2011-01-01

    Background Metal Inert Gas (MIG) welding and Tungsten Inert Gas (TIG) welding are widely used for mild steel segments in basic metal industries. Pulmonary problems such as asthma, pulmonary inflammation, hyper-responsiveness of airways and higher susceptibility to infections are reported as the result of occupational exposure of welders to ozone and nitrogen oxides. Potent oxidizing agents like ozone and nitrogen oxides are also reported to be a precursor for respiratory problems and cause lipid peroxidation of membranes. Materials and Methods A total of 43 nonsmoking MIG and TIG welders and 41 nonsmoking workers without appreciable exposure to any chemicals as the control population were chosen to participate in this study. Occupational exposure to ozone was monitored according to the validated methods. Malondialdehyde (MDA) of blood serum as a biomarker for lipid peroxidation was analyzed using Reverse Phase High Performance Liquid Chromatography. Data obtained from this study were analyzed using t-test, Pearson's correlation coefficient and multiple regression analysis. Results A total of 88.4% and 74.4% of welders had exposure to ozone and nitrogen dioxide higher than the permissible limit of occupational exposure, respectively. Generally, exposure of MIG welders to ozone was significantly higher than TIG welders (P = 0.006). However, exposure to nitrogen dioxide gas was comparable in both groups. Serum MDA of welders was significantly higher than that of the control group (P = 0.001). A significant correlation was detected between ozone exposure and level of serum malondialdehyde. Such correlation was not observed for nitrogen dioxide exposure. Conclusion Considering the high exposure of welders to ozone and nitrogen dioxide, and higher level of serum malondialdehyde in them compared to controls, risk management is recommended for this group of workers. PMID:25191389

  20. Prolonged Exposure for Guilt and Shame in a Veteran of Operation Iraqi Freedom

    PubMed Central

    Paul, Lisa A.; Gros, Daniel F.; Strachan, Martha; Worsham, Glenna; Foa, Edna B.; Acierno, Ron

    2014-01-01

    Morally injurious events appear capable of producing posttraumatic stress disorder (PTSD), even though they may not involve actual or perceived life-threat or a response of fear, horror, or helplessness. Researchers have questioned whether exposure therapies can address these events. The current report presents evidence of the effectiveness of this treatment approach for addressing posttraumatic symptoms related to a morally injurious event through an illustrative case of an Operation Iraqi Freedom veteran with PTSD characterized by symptoms of guilt and shame. The veteran was successfully treated with nine sessions of prolonged exposure therapy, reporting minimal PTSD symptoms one week post-treatment and at a six-month follow-up assessment. Implications for the treatment of veterans with significant guilt and shame using exposure-based therapies, and with respect to the recent changes to the diagnostic criteria for PTSD, are discussed. PMID:25505798

  1. Ozone exposure and systemic biomarkers: Evaluation of evidence for adverse cardiovascular health impacts.

    PubMed

    Goodman, Julie E; Prueitt, Robyn L; Sax, Sonja N; Pizzurro, Daniella M; Lynch, Heather N; Zu, Ke; Venditti, Ferdinand J

    2015-05-01

    The US Environmental Protection Agency (EPA) recently concluded that there is likely to be a causal relationship between short-term (< 30 days) ozone exposure and cardiovascular (CV) effects; however, biological mechanisms to link transient effects with chronic cardiovascular disease (CVD) have not been established. Some studies assessed changes in circulating levels of biomarkers associated with inflammation, oxidative stress, coagulation, vasoreactivity, lipidology, and glucose metabolism after ozone exposure to elucidate a biological mechanism. We conducted a weight-of-evidence (WoE) analysis to determine if there is evidence supporting an association between changes in these biomarkers and short-term ozone exposure that would indicate a biological mechanism for CVD below the ozone National Ambient Air Quality Standard (NAAQS) of 75 parts per billion (ppb). Epidemiology findings were mixed for all biomarker categories, with only a few studies reporting statistically significant changes and with no consistency in the direction of the reported effects. Controlled human exposure studies of 2 to 5 hours conducted at ozone concentrations above 75 ppb reported small elevations in biomarkers for inflammation and oxidative stress that were of uncertain clinical relevance. Experimental animal studies reported more consistent results among certain biomarkers, although these were also conducted at ozone exposures well above 75 ppb and provided limited information on ozone exposure-response relationships. Overall, the current WoE does not provide a convincing case for a causal relationship between short-term ozone exposure below the NAAQS and adverse changes in levels of biomarkers within and across categories, but, because of study limitations, they cannot not provide definitive evidence of a lack of causation.

  2. Surface morphology and morphometry of rat alveolar macrophages after ozone exposure

    SciTech Connect

    Dormans, J.A.; Rombout, P.J.; van Loveren, H. )

    1990-09-01

    As the ultrastructural data on the effects of ozone on pulmonary alveolar macrophages (PAM) are lacking, transmission (TEM) and scanning (SEM) electron microscopy were performed on rat PAM present in alveolar lavages following exposure to ozone. Rats were continuously exposed for 7 d to ozone concentrations ranging from 0.25 to 1.50 mg/m3 for 7 d followed by a 5-d recovery period. Additionally, morphometry on lung sections was performed to quantitate PAM. In a second experiment rats were continuously exposed to 1.50 mg O3/m3 for 1, 3, 5, or 7 d. To study the influence of concurrent ozone exposure and lung infection, due to Listeria monocytogenes, rats were exposed for 7 d to 1.50 mg O3/m3 after a Listeria infection. The surface area of lavaged control PAM was uniformly covered with ruffles as shown by SEM and TEM. Exposure to 0.5 mg ozone/m3 for 7 d resulted in cells partly covered with microvilli and blebs in addition to normal ruffles. The number of large size PAM increased with an increase in ozone concentration. After 1 d of exposure, normal-appearing as well as many small macrophages with ruffles and scattered lymphocytes were seen. Lavage samples taken after 5 or 7 d of exposure showed an identical cell composition to that taken after 3 d of exposure. After Listeria infection alone, lavage samples consisted of mainly lymphocytes and some macrophages. Small quantitative changes, such as an increase in the number of polymorphonuclear neutrophils and large-size PAM, occurred in lavages after ozone exposure and infection with L. monocytogenes. Morphometric examination of lung sections revealed a concentration-related increase in the number of PAM, even in animals exposed to 0.25 mg ozone/m3 for 7 d. Centriacinar regions were more severely affected than other regions of lung tissue.

  3. Ozone exposure and systemic biomarkers: Evaluation of evidence for adverse cardiovascular health impacts.

    PubMed

    Goodman, Julie E; Prueitt, Robyn L; Sax, Sonja N; Pizzurro, Daniella M; Lynch, Heather N; Zu, Ke; Venditti, Ferdinand J

    2015-05-01

    The US Environmental Protection Agency (EPA) recently concluded that there is likely to be a causal relationship between short-term (< 30 days) ozone exposure and cardiovascular (CV) effects; however, biological mechanisms to link transient effects with chronic cardiovascular disease (CVD) have not been established. Some studies assessed changes in circulating levels of biomarkers associated with inflammation, oxidative stress, coagulation, vasoreactivity, lipidology, and glucose metabolism after ozone exposure to elucidate a biological mechanism. We conducted a weight-of-evidence (WoE) analysis to determine if there is evidence supporting an association between changes in these biomarkers and short-term ozone exposure that would indicate a biological mechanism for CVD below the ozone National Ambient Air Quality Standard (NAAQS) of 75 parts per billion (ppb). Epidemiology findings were mixed for all biomarker categories, with only a few studies reporting statistically significant changes and with no consistency in the direction of the reported effects. Controlled human exposure studies of 2 to 5 hours conducted at ozone concentrations above 75 ppb reported small elevations in biomarkers for inflammation and oxidative stress that were of uncertain clinical relevance. Experimental animal studies reported more consistent results among certain biomarkers, although these were also conducted at ozone exposures well above 75 ppb and provided limited information on ozone exposure-response relationships. Overall, the current WoE does not provide a convincing case for a causal relationship between short-term ozone exposure below the NAAQS and adverse changes in levels of biomarkers within and across categories, but, because of study limitations, they cannot not provide definitive evidence of a lack of causation. PMID:25959700

  4. Effects of prolonged exposure to perchlorate on thyroid and reproductive function in zebrafish

    USGS Publications Warehouse

    Mukhi, S.; Patino, R.

    2007-01-01

    The objectives of this study were to determine the effects of prolonged exposure to perchlorate on (1) thyroid status and reproductive performance of adult zebrafish (Danio rerio) and (2) F1 embryo survival and early larval development. Using a static-renewal procedure, mixed sex populations of adult zebrafish were exposed to 0, 10, and 100 mg/l nominal concentrations of waterborne perchlorate for 10 weeks. Thyroid histology was qualitatively assessed, and females and males were separated and further exposed to their respective treatments for six additional weeks. Eight females in each tank replicate (n = 3) were paired weekly with four males from the same respective treatment, and packed-egg (spawn) volume (PEV) was measured each of the last five weeks. At least once during weeks 14-16 of exposure, other end points measured included fertilization rate, fertilized egg diameter, hatching rate, standard length, and craniofacial development of 4-day-postfertilization larvae and thyroid hormone content of 3.5-h embryos and of exposed mothers. At 10 weeks of exposure, perchlorate at both concentrations caused thyroidal hypertrophy and colloid depletion. A marked reduction in PEV was observed toward the end of the 6-week spawning period, but fertilization and embryo hatching rates were unaffected. Fertilized egg diameter and larval length were increased by parental exposure to perchlorate. Larval head depth was unaffected but the forward protrusion of the lower jaw-associated cartilage complexes, Meckel's and ceratohyal, was decreased. Exposure to both concentrations of perchlorate inhibited whole-body thyroxine content in mothers and embryos, but triiodothyronine content was unchanged. In conclusion, prolonged exposure of adult zebrafish to perchlorate not only disrupts their thyroid endocrine system but also impairs reproduction and influences early F1 development. ?? 2007 Oxford University Press.

  5. Pulmonary function and symptom responses after 6. 6-hour exposure to 0. 12 ppm ozone with moderate exercise

    SciTech Connect

    Folinsbee, L.J.; McDonnell, W.F.; Horstman, D.H.

    1988-01-01

    Episodes occasionally occur when ambient ozone (O/sub 3/) levels remain at or near 0.12 ppm for more than 6 h. Small decrements in lung function have been reported following 2-h exposures to 0.12 ppm O/sub 3/. For short exposures to higher O/sub 3/ concentrations, lung function decrements are a function of exposure duration. Thus, we investigated the hypothesis that prolonged exposure to 0.12 ppm O/sub 3/ would result in progressively larger changes in respiratory function and symptoms over time. Ten nonsmoking males were exposed once to clean air and once to 0.12 ppm O/sub 3/ for 6.6 h. Exposures consisted of six 50-min exercise periods, each followed by 10-min rest and measurement; a 35-min lunch period followed by the third exercise period. Exercise ventilation averaged approximately 40 L/min. Forced expiratory and inspiratory spirometry and respiratory symptoms were measured prior to exposure and after each exercise. Airway reactivity to methacholine was determined after each exposure. After correcting for the air exposures, FEV 1.0 was found to decrease linearly during the O/sub 3/ exposure and was decreased by an average of 13.0 percent at the end of exposure. Decreases in FVC and FEF24-75% were also linear and averaged 8.3 and 17.4 percent, respectively, at the end of exposure. On forced inspiratory tests, the FIVC and FIV05 were decreased 12.6 and 20.7 percent, respectively. Increases in the symptom ratings of cough and pain on deep inspiration were observed with O/sub 3/ exposure but not with clean air. Airway reactivity to methacholine was approximately doubled following O/sub 3/ exposure.

  6. Adjoint-based computation of U.S. nationwide ozone exposure isopleths

    NASA Astrophysics Data System (ADS)

    Ashok, Akshay; Barrett, Steven R. H.

    2016-05-01

    Population exposure to daily maximum ozone is associated with an increased risk of premature mortality, and efforts to mitigate these impacts involve reducing emissions of nitrogen oxides (NOx) and volatile organic compounds (VOCs). We quantify the dependence of U.S. national exposure to annually averaged daily maximum ozone on ambient VOC and NOx concentrations through ozone exposure isopleths, developed using emissions sensitivities from the adjoint of the GEOS-Chem air quality model for 2006. We develop exposure isopleths for all locations within the contiguous US and derive metrics based on the isopleths that quantify the impact of emissions on national ozone exposure. This work is the first to create ozone exposure isopleths using adjoint sensitivities and at a large scale. We find that across the US, 29% of locations experience VOC-limited conditions (where increased NOx emissions lower ozone) during 51% of the year on average. VOC-limited conditions are approximately evenly distributed diurnally and occur more frequently during the fall and winter months (67% of the time) than in the spring and summer (37% of the time). The VOC/NOx ratio of the ridge line on the isopleth diagram (denoting a local maximum in ozone exposure with respect to NOx concentrations) is 9.2 ppbC/ppb on average across grid cells that experience VOC-limited conditions and 7.9, 10.1 and 6.7 ppbC/ppb at the three most populous US cities of New York, Los Angeles and Chicago, respectively. Emissions that are ozone exposure-neutral during VOC-limited exposure conditions result in VOC/NOx concentration ratios of 0.63, 1.61 and 0.72 ppbC/ppb at each of the three US cities respectively, and between 0.01 and 1.91 ppbC/ppb at other locations. The sensitivity of national ozone exposure to NOx and VOC emissions is found to be highest near major cities in the US. Together, this information can be used to assess the effectiveness of NOx and VOC emission reductions on mitigating ozone exposure in the

  7. Threshold exceedances and cumulative ozone exposure indices at tropical suburban site

    NASA Astrophysics Data System (ADS)

    Beig, G.; Ghude, Sachin D.; Polade, S. D.; Tyagi, B.

    2008-01-01

    This study provides the first analysis of threshold exceedances and cumulative ozone exposure indices from Pune, a tropical suburban site in India. We used the directives on ozone pollution in ambient air provided by the United Nations Economic Commission for Europe, and by the World Health Organization to assess the air quality from in situ measurements of surface ozone (during the years 2003-2006). We find that the exposure-plant response index (Accumulated exposure Over a Threshold of 40 ppb (AOT40)) and target values for protection of human health (8-h > 60 ppb) are regularly surpassed. This is a concern for agricultural and human health. Air-mass classification based on back-air trajectories shows that the excess of AOT40 values is quite plausibly due to long-range transport of background ozone and its precursors to the measurement site.

  8. The effects of different ozone exposures on three contrasting populations of Plantago major.

    PubMed

    Pearson, S; Davison, A W; Reiling, K; Ashenden, T; Ollerenshaw, J H

    1996-03-01

    Plantago major grows throughout Britain in a range of ozone climates. Because populations have been shown to differ in ozone resistance, the aim of the experiment was to compare the reaction of populations from contrasting ozone climates to different types of ozone exposure. Three populations were grown under controlled conditions in five different ozone treatments (including controls for 10 wk. Development, growth, stomatal conductance and seed production were recorded. Populations were from the south coast of England (Lullington), near a mountain summit (Great Dun Fell) and lowland Scotland (Bush). Ozone treatments were: charcoal and Purafil filtered air (CF); 35 nl l(-1) for 24 h every day: 70 nl l(-1) h for 7 h everyday: CF then three episodes each week of 70 nl l(-1) for 7 h; and 35 nl l(-1) continuously plus three 7 h episodes each week of 70 nl l(-1) . The different ozone treatments resulted in different responses in each population. Ozone promoted senescence in the Great Dun Fell population but not in the others; it reduced root growth more in the Lullington population than in the others but those from Lullington and Great Dun Fell maintained seed production to a much greater extent than the Bush population. The reproductive effort (number of seeds g(-1) of vegetative weight) actually increased in ozone in the Lullington and Great Dun Fell populations. It is suggested that this might he a general stress response rather than being specifically related to ozone. Effects on stomatal conductance were similar to those previously reported and the converse of effects on seed production. The relative responses of the populations varied according to the ozone treatment. Continuous exposure to 35 n1 l(-l) reduced leaf size only in the Great Dun Fell population, but seed output was reduced in the Bush population. In some cases, giving 3-d episodes of 70 n1 l(-1) had a greater effect than giving the dose every day but the effects varied with the population. This

  9. The effects of different ozone exposures on three contrasting populations of Plantago major.

    PubMed

    Pearson, S; Davison, A W; Reiling, K; Ashenden, T; Ollerenshaw, J H

    1996-03-01

    Plantago major grows throughout Britain in a range of ozone climates. Because populations have been shown to differ in ozone resistance, the aim of the experiment was to compare the reaction of populations from contrasting ozone climates to different types of ozone exposure. Three populations were grown under controlled conditions in five different ozone treatments (including controls for 10 wk. Development, growth, stomatal conductance and seed production were recorded. Populations were from the south coast of England (Lullington), near a mountain summit (Great Dun Fell) and lowland Scotland (Bush). Ozone treatments were: charcoal and Purafil filtered air (CF); 35 nl l(-1) for 24 h every day: 70 nl l(-1) h for 7 h everyday: CF then three episodes each week of 70 nl l(-1) for 7 h; and 35 nl l(-1) continuously plus three 7 h episodes each week of 70 nl l(-1) . The different ozone treatments resulted in different responses in each population. Ozone promoted senescence in the Great Dun Fell population but not in the others; it reduced root growth more in the Lullington population than in the others but those from Lullington and Great Dun Fell maintained seed production to a much greater extent than the Bush population. The reproductive effort (number of seeds g(-1) of vegetative weight) actually increased in ozone in the Lullington and Great Dun Fell populations. It is suggested that this might he a general stress response rather than being specifically related to ozone. Effects on stomatal conductance were similar to those previously reported and the converse of effects on seed production. The relative responses of the populations varied according to the ozone treatment. Continuous exposure to 35 n1 l(-l) reduced leaf size only in the Great Dun Fell population, but seed output was reduced in the Bush population. In some cases, giving 3-d episodes of 70 n1 l(-1) had a greater effect than giving the dose every day but the effects varied with the population. This

  10. Response of different-aged black cherry trees to ambient ozone exposure

    SciTech Connect

    Fredericksen, T.S.; Joyce, B.J.; Kouterick, K.B.; Kolb, T.E.; Skelly, J.M.; Steiner, K.C.; Savage, J.E.; Snyder, K.R. )

    1994-06-01

    Black cherry (Prunus serotina Ehrh.) is a valuable commercial timber species which is also highly sensitive to ozone relative to other eastern deciduous tree species. Studies of ozone effects on forest trees have been restricted mostly to experiments using small seedlings under controlled conditions. Yet, mature trees may differ from seedlings in physiology, morphology, and exposure to air pollutants. An experiment was conducted in 1993 to determine differences in ozone uptake and foliar injury symptoms between open-ground seedlings, forest saplings, and mature forest trees of black cherry in northcentral Pennsylvania. Seedlings grew under the highest ozone concentrations and also had greater seasonal ozone uptake due to higher rates of stomatal conductance. However, because of their indeterminate growth habit, seedlings had lower cumulative ozone uptake per leaf lifespan than saplings or mature trees, both of which had determinate shoot growth. Although greater initially for seedlings, foliar injury was nearly identical between size classes by the end of the growing season. Leaves in the lower crown of larger trees had lower ozone uptake than leaves in the upper crown, but exhibited more foliar injury symptoms. Lower crown leaves received more effective exposure to ozone because of their thinner leaves and had less available photosynthate for repair or replacement of damaged tissue.

  11. Human physiological responses to cold exposure: Acute responses and acclimatization to prolonged exposure.

    PubMed

    Castellani, John W; Young, Andrew J

    2016-04-01

    Cold exposure in humans causes specific acute and chronic physiological responses. This paper will review both the acute and long-term physiological responses and external factors that impact these physiological responses. Acute physiological responses to cold exposure include cutaneous vasoconstriction and shivering thermogenesis which, respectively, decrease heat loss and increase metabolic heat production. Vasoconstriction is elicited through reflex and local cooling. In combination, vasoconstriction and shivering operate to maintain thermal balance when the body is losing heat. Factors (anthropometry, sex, race, fitness, thermoregulatory fatigue) that influence the acute physiological responses to cold exposure are also reviewed. The physiological responses to chronic cold exposure, also known as cold acclimation/acclimatization, are also presented. Three primary patterns of cold acclimatization have been observed, a) habituation, b) metabolic adjustment, and c) insulative adjustment. Habituation is characterized by physiological adjustments in which the response is attenuated compared to an unacclimatized state. Metabolic acclimatization is characterized by an increased thermogenesis, whereas insulative acclimatization is characterized by enhancing the mechanisms that conserve body heat. The pattern of acclimatization is dependent on changes in skin and core temperature and the exposure duration.

  12. Human physiological responses to cold exposure: Acute responses and acclimatization to prolonged exposure.

    PubMed

    Castellani, John W; Young, Andrew J

    2016-04-01

    Cold exposure in humans causes specific acute and chronic physiological responses. This paper will review both the acute and long-term physiological responses and external factors that impact these physiological responses. Acute physiological responses to cold exposure include cutaneous vasoconstriction and shivering thermogenesis which, respectively, decrease heat loss and increase metabolic heat production. Vasoconstriction is elicited through reflex and local cooling. In combination, vasoconstriction and shivering operate to maintain thermal balance when the body is losing heat. Factors (anthropometry, sex, race, fitness, thermoregulatory fatigue) that influence the acute physiological responses to cold exposure are also reviewed. The physiological responses to chronic cold exposure, also known as cold acclimation/acclimatization, are also presented. Three primary patterns of cold acclimatization have been observed, a) habituation, b) metabolic adjustment, and c) insulative adjustment. Habituation is characterized by physiological adjustments in which the response is attenuated compared to an unacclimatized state. Metabolic acclimatization is characterized by an increased thermogenesis, whereas insulative acclimatization is characterized by enhancing the mechanisms that conserve body heat. The pattern of acclimatization is dependent on changes in skin and core temperature and the exposure duration. PMID:26924539

  13. Studying cumulative ozone exposures in Europe during a 7-year period

    NASA Astrophysics Data System (ADS)

    Bastrup-Birk, Annemarie; Brandt, JøRgen; Zlatev, Zahari; Uria, Ignacio

    1997-10-01

    Ozone is one of the most harmful pollutants in the troposphere. High ozone concentrations can damage plants, animals and humans. The damaging effects depend on the magnitude of a critical level of a special parameter, the cumulative ozone exposure. This is why cumulative ozone exposures must be carefully studied. It is important to determine the relationships between relevant emissions (NOx emissions, human-made VOC emissions, and/or a combination of NOx emissions and human-made VOC emissions) and cumulative ozone exposures. All these issues are discussed in this paper. Meteorological data from seven consecutive years, from 1989 to 1995, have been used in the experiments with different scenarios for varying the emissions (the NOx emissions, the human-made VOC emissions, as well as both the NOx emissions and the human-made VOC emissions). The particular air pollution model used in this study is the Danish Eulerian Model. Several hundred runs with different input data (meteorological data and/or emission data) have been performed. Advanced visualization techniques are used to interpret the large amount of digital data collected in these runs and to show clearly different trends and relationships that are normally hidden behind millions and millions of numbers. The model results were compared with measurements taken at more than 80 stations located in different European countries. The experiments indicate that it is sufficient to carry out computations over 5 consecutive years in order to eliminate the influence of extreme meteorological conditions (very warm or very cold summer months) on the cumulative ozone exposures, while this effect is clearly seen if less than 5 years are used in the experiments. It is shown that the relationship between the emissions (NOx and/or human-made VOC emissions) and the cumulative ozone exposures is in general nonlinear. Finally, it is illustrated that the critical values for ozone exposures are exceeded in most of Europe (in many

  14. Responses of subjects with chronic obstructive pulmonary disease after exposures to 0. 3 ppm ozone

    SciTech Connect

    Kehrl, H.R.; Hazucha, M.J.; Solic, J.J.; Bromberg, P.A.

    1985-05-01

    The authors previously reported that the respiratory mechanics of intermittently exercising persons with chronic obstructive pulmonary disease (COPD) were unaffected by a 2-h exposure to 0.2 ppm ozone. Employing a single-blind, cross-over design protocol, 13 white men with nonreversible COPD (9 current smokers; mean FEV1/FVC, 56%) were randomly exposed on 2 consecutive days for 2 h to air and 0.3 ppm ozone. During exposures, subjects exercised (minute ventilation, 26.4 +/- 3.0 L/min) for 7.5 min every 30 min; ventilation and gas exchange measured during exercise showed no difference between exposure days. Pulmonary function tests (spirometry, body plethysmography) obtained before and after exposures were unchanged on the air day. On the ozone day the mean airway resistance and specific airway resistance showed the largest (25 and 22%) changes (p = 0.086 and 0.058, respectively). Arterial oxygen saturation (SaO/sub 2/) obtained in 8 subjects during the last exercise interval showed a mean decrement of 0.95% on the ozone exposure day; this change did not attain significance (p = 0.074). Nevertheless, arterial oxygen desaturation may be a true consequence of low-level ozone exposure in this compromised patient group. As normal subjects undergoing exposures to ozone with slightly higher exercise intensities show a threshold for changes in their respiratory mechanics at approximately 0.3 ppm, these data indicate that persons with COPD are not unduly sensitive to the effects of low-level ozone exposure.

  15. Changes in neuroreceptor function of tracheal smooth muscle following acute ozone exposure of guinea pigs.

    PubMed

    van Hoof, H J; Voss, H P; Kramer, K; Boere, A J; Dormans, J A; van Bree, L; Bast, A

    1997-07-11

    We studied the effect of in vivo ozone inhalation (3 ppm, 2 h) on neuroreceptor function in guinea pig tracheal smooth muscle in vitro and the role of the epithelial layer in this process. Changes in smooth muscle tension after stimulation of the muscarinic- and beta-adrenergic receptor were recorded isometrically and stained tracheal tissue sections were histologically evaluated for changes in the epithelial and smooth muscle layer. Ozone exposure resulted in an increase in maximal contraction following stimulation of the muscarinic receptor, whereas pD2 values remained unchanged. After stimulation of the beta-adrenergic receptor no increase in maximal relaxation but only an increase in pD2 value was observed after correction for differences in precontraction level in control- and ozone-exposed situations. Mechanical removal of the epithelial layer resulted in a slight increase of the maximal contraction level after stimulation with methacholine in the control situation, whereas exposure to ozone resulted in a strong decrease of the maximal contraction level under these conditions. Histological stainings showed a slight and focal influx of neutrophilic granulocytes in the epithelial layer, submucosal layer and airway lumen after exposure to ozone. These data support the idea that ozone is able to increase the maximal degree of airway narrowing upon muscarinergic stimulation, i.e. a hyperreactivity response. The results also suggest that functionally altered epithelium plays an important role in the process of ozone-induced hyperreactivity, possibly linked with an early inflammatory response.

  16. Species differences in impairment and recovery of alveolar macrophage functions following single and repeated ozone exposures

    SciTech Connect

    Oosting, R.S.; van Golde, L.M.; Verhoef, J.; Van Bree, L. )

    1991-08-01

    Effects of single (0.4 ppm for 3, 6, or 12 hr) and repeated (0.4 ppm, 12 hr/day for 3 or 7 days) in vivo ozone exposures on rat and mouse alveolar macrophage functions and cell number were investigated. Single ozone exposure of rats resulted in a small (approximately 15%) decrease in Fc-receptor-mediated phagocytosis and phorbol ester-induced superoxide production by the alveolar macrophages and was followed by recovery above control levels within 12 hr of exposure. Repeated exposures of rats for up to 7 days did not alter alveolar macrophage functions, with the exception of the effects of 3 days of exposure on superoxide production (71 {plus minus} 9% as compared with the controls). In mice, significant changes in alveolar macrophage functions were not observed until 12 hr of exposure (at that timepoint phagocytosis was 74 {plus minus} 2%). Repeated ozone exposures of mice did not cause a further decrease in phagocytosis (at Day 7, 74 {plus minus} 14%). Both after 3 and 7 days of repeated ozone exposure of mice, superoxide production by the alveolar macrophages was inhibited approximately 50%. In rats and mice, repeated ozone exposures led to an increase in the number of alveolar macrophages. In mice, this increase appeared at a later time point (at Day 7 vs Day 3) and was less pronounced (at Day 7, 139 {plus minus} 9% vs 179 {plus minus} 17%) as compared with rats. In summary, our data show that rat and mouse alveolar macrophages have different susceptibilities to both single and repeated in vivo ozone exposures.

  17. Ozone

    MedlinePlus

    ... reactive form of oxygen. In the upper atmosphere, ozone forms a protective layer that shields us from the sun’s ultraviolet rays. At ground level, ozone is a harmful air pollutant and a primary ...

  18. Exposure to ozone modulates human airway protease/antiprotease balance contributing to increased influenza A infection.

    PubMed

    Kesic, Matthew J; Meyer, Megan; Bauer, Rebecca; Jaspers, Ilona

    2012-01-01

    Exposure to oxidant air pollution is associated with increased respiratory morbidities and susceptibility to infections. Ozone is a commonly encountered oxidant air pollutant, yet its effects on influenza infections in humans are not known. The greater Mexico City area was the primary site for the spring 2009 influenza A H1N1 pandemic, which also coincided with high levels of environmental ozone. Proteolytic cleavage of the viral membrane protein hemagglutinin (HA) is essential for influenza virus infectivity. Recent studies suggest that HA cleavage might be cell-associated and facilitated by the type II transmembrane serine proteases (TTSPs) human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2), whose activities are regulated by antiproteases, such as secretory leukocyte protease inhibitor (SLPI). Based on these observations, we sought to determine how acute exposure to ozone may modulate cellular protease/antiprotease expression and function, and to define their roles in a viral infection. We utilized our in vitro model of differentiated human nasal epithelial cells (NECs) to determine the effects of ozone on influenza cleavage, entry, and replication. We show that ozone exposure disrupts the protease/antiprotease balance within the airway liquid. We also determined that functional forms of HAT, TMPRSS2, and SLPI are secreted from human airway epithelium, and acute exposure to ozone inversely alters their expression levels. We also show that addition of antioxidants significantly reduces virus replication through the induction of SLPI. In addition, we determined that ozone-induced cleavage of the viral HA protein is not cell-associated and that secreted endogenous proteases are sufficient to activate HA leading to a significant increase in viral replication. Our data indicate that pre-exposure to ozone disrupts the protease/antiprotease balance found in the human airway, leading to increased influenza susceptibility. PMID

  19. Exposure to Ozone Modulates Human Airway Protease/Antiprotease Balance Contributing to Increased Influenza A Infection

    PubMed Central

    Kesic, Matthew J.; Meyer, Megan; Bauer, Rebecca; Jaspers, Ilona

    2012-01-01

    Exposure to oxidant air pollution is associated with increased respiratory morbidities and susceptibility to infections. Ozone is a commonly encountered oxidant air pollutant, yet its effects on influenza infections in humans are not known. The greater Mexico City area was the primary site for the spring 2009 influenza A H1N1 pandemic, which also coincided with high levels of environmental ozone. Proteolytic cleavage of the viral membrane protein hemagglutinin (HA) is essential for influenza virus infectivity. Recent studies suggest that HA cleavage might be cell-associated and facilitated by the type II transmembrane serine proteases (TTSPs) human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2), whose activities are regulated by antiproteases, such as secretory leukocyte protease inhibitor (SLPI). Based on these observations, we sought to determine how acute exposure to ozone may modulate cellular protease/antiprotease expression and function, and to define their roles in a viral infection. We utilized our in vitro model of differentiated human nasal epithelial cells (NECs) to determine the effects of ozone on influenza cleavage, entry, and replication. We show that ozone exposure disrupts the protease/antiprotease balance within the airway liquid. We also determined that functional forms of HAT, TMPRSS2, and SLPI are secreted from human airway epithelium, and acute exposure to ozone inversely alters their expression levels. We also show that addition of antioxidants significantly reduces virus replication through the induction of SLPI. In addition, we determined that ozone-induced cleavage of the viral HA protein is not cell-associated and that secreted endogenous proteases are sufficient to activate HA leading to a significant increase in viral replication. Our data indicate that pre-exposure to ozone disrupts the protease/antiprotease balance found in the human airway, leading to increased influenza susceptibility. PMID

  20. Response of Phaseolus vulgaris L. to differing ozone regimes having identical total exposure

    NASA Astrophysics Data System (ADS)

    Musselman, Robert C.; Younglove, Theodore; McCool, Patrick M.

    Protocols were designed to test for differences in response of plants to ozone treatments having equal total exposure (concentration × time) but different exposure profiles Kidney beans ( Phaseolus vulgaris L., cv. California Dark Red) were exposed to ozone in controlled fumigation chambers within a greenhouse Four different ozone exposure profiles were used, each having the same total cumulative exposure (SUM00) and the same 7, 12 and 24 h seasonal means. The three exposure profiles which incorporated peak concentrations more severely impacted response parameters compared to a steady-state profile which did not exceed the National Ambient Air Quality Standard. Significant differences were found in percent necrotic leaf area, number of pods and top dry weight between exposure profiles. In additional analyses, the response parameters were regressed against seasonal cumulative ozone concentrations raised to powers of 0.33 and from 0.5 to 4 in steps of 0.5 in order to increase effective weighting of the higher concentrations. Total dry weight and leaf necrosis were best fit with the sum of the squared concentrations ( n = 2) while number of pods was best fit by the summed concentrations to the 3.5 power ( n = 3.5). These analyses suggest the peak ozone concentrations are important in determining plant response.

  1. The effect of prolonged exposure to 750 C air on the tribological performance of PM212

    NASA Technical Reports Server (NTRS)

    Bemis, Kirk; Bogdanski, Michael S.; Dellacorte, Christopher; Sliney, Harold E.

    1994-01-01

    The effect of prolonged exposure to 750 C air on the tribological performance and dimensional stability of PM212, a high temperature, self-lubricating composite, is studied. PM212, by weight, contains 70 percent metal-bonded Cr3C2, 15 percent BaF2/CaF2 eutectic, and 15 percent silver. Rub blocks were fabricated from PM212 by cold isostatic pressing followed by sintering. Prior to tribo-testing, the rub blocks were exposed to 750 C air for periods ranging from 100 to 1000 hours. Then, the rub blocks were slid against nickel-based superalloy disks in a double-rub-block tribometer in air under a 66 N load at temperatures from 25 to 750 C with a sliding velocity of 0.36 m/s. Unexposed rub blocks were tested for baseline comparison. Friction coefficients ranged from 0.24 to 0.37 for the unexposed rub blocks and from 0.32 to 0.56 for the exposed ones. Wear for both the composite blocks and superalloy disks was typically in the moderate to low range of 10(exp -5) to 10(exp -6) mm(exp 3)/N-m. Friction and wear data were similar for the rub blocks exposed for 100, 500, and 1000 hours. Prolonged exposure to 750 C air increased friction and wear of the PM212 rub blocks at room temperature, but their triboperformance remained unaffected at higher temperatures, probably due to the formation of lubricious metal oxides. Dimensional stability of the composite was studied by exposing specimens of varying thicknesses for 500 hours in air at 750 C. Block thicknesses were found to increase with increased exposure time until steady state was reached after 100 hours of exposure, probably due to oxidation.

  2. Ozone

    MedlinePlus

    Ozone is a gas. It can be good or bad, depending on where it is. "Good" ozone occurs naturally about 10 to 30 miles above ... the sun's ultraviolet rays. Part of the good ozone layer is gone. Man-made chemicals have destroyed ...

  3. Attenuation of signaling and nitric oxide production following prolonged leptin exposure in human aortic endothelial cells.

    PubMed

    Blanquicett, Carmelo; Graves, Anitra; Kleinhenz, Dean J; Hart, C Michael

    2007-11-01

    Acute leptin exposure stimulates endothelial nitric oxide (NO) production in vitro. In contrast, chronic elevations in circulating leptin levels in patients with obesity are associated with endothelial dysfunction and impaired endothelial NO production. Therefore, the goal of the current study was to examine the direct effects of acute and more sustained leptin stimulation on endothelial nitric oxide synthase (eNOS) and NO production in human aortic endothelial cells (HAECs). HAECs were treated with vehicle or with leptin (5 or 60 ng/mL) acutely (30-60 minutes) or for 72 hours. HAEC NO release into culture media was measured with a chemiluminescence technique, and superoxide (O(2)(-.)) production was measured with electron spin resonance (ESR) spectroscopy. HAEC eNOS activity was measured as the conversion of (3)H-arginine to (3)H-citrulline, and protein levels of eNOS, phospho-eNOS (serine 1177), Erk, phospho-Erk, suppressor of cytokine signaling (SOCS3), xanthine oxidase (XO), and the reduced nicotinamide adenine dinucleotide (NADPH) oxidase components p22phox, p67phox, Nox-4, and gp91phox were examined by Western blotting or immunoprecipitation. Acute leptin exposure increased eNOS serine 1177 phosphorylation and caused Erk activation. In contrast, prolonged leptin stimulation was not cytotoxic and failed to alter eNOS expression, phosphorylation, or HAEC NO release. Furthermore, prolonged leptin stimulation did not alter O(2)(-.) production or NADPH oxidase or XO expression but increased SOCS3 expression. In contrast to acute stimulation, prolonged (72 hours) stimulation does not alter endothelial cell NO or O(2)(-.) production. We postulate that chronic leptin stimulation, through increased SOCS3 expression, may attenuate the effects of leptin on vascular endothelial function. PMID:18062898

  4. DEVELOMENT AND EVALUATION OF A MODEL FOR ESTIMATING LONG-TERM AVERAGE OZONE EXPOSURES TO CHILDREN

    EPA Science Inventory

    Long-term average exposures of school-age children can be modelled using longitudinal measurements collected during the Harvard Southern California Chronic Ozone Exposure Study over a 12-month period: June, 1995-May, 1996. The data base contains over 200 young children with perso...

  5. OZONE-INDUCED RESPIRATORY SYMPTOMS: EXPOSURE-RESPONSE MODELS AND ASSOCIATION WITH LUNG FUNCTION

    EPA Science Inventory

    Ozone-induced respiratory symptoms are known to be functions of concentration, minute ventilation, and duration of exposure. The purposes of this study were to identify an exposure-response model for symptoms, to determine whether response was related to age, and to assess the re...

  6. Duration of increased pulmonary function sensitivity to an initial ozone exposure

    SciTech Connect

    Bedi, J.F.; Drechsler-Parks, D.M.; Horvath, S.M.

    1985-12-01

    The metabolic and pulmonary function effects were investigated in six non-smoking young adults who were exposed for 2 hours (22 degrees C WBGT) to: filtered air (FA) 0.45 ppm ozone (DAY1); and two days later to a second exposure to 0.45 ppm ozone (DAY2). The subjects alternated 20-minute periods of rest and 20-minute periods of bicycle ergometer exercise at a workload predetermined to elicit a ventilatory minute volume (VE) of 27 L/min (BTPS). Functional residual capacity (FRC) was determined pre- and post-exposure. Forced vital capacity (FVC) was determined before and after exposure, as well as 5 minutes after each exercise period. Heart rate was monitored throughout the exposure, and VE, oxygen uptake (VO2), respiratory rate (fR), and tidal volume (VT) were measured during the last 2 minutes of each exercise period. There were no changes in any variable consequent to FA exposure. Both ozone exposures induced significant (P less than 0.05) decrements in FVC; FEV1.0 (forced expiratory volume in 1 second); FEV3.0 (forced expiratory volume in 3 seconds); FEF25-75% (average flow rate between 25% and 75% of FVC); and total lung capacity (TLC). The decrements following the DAY2 ozone exposure were significantly greater than following DAY1, and averaged 7.2 percentage points greater than those following the DAY1 exposure.

  7. Prolonged exposure to arsenic in UK private water supplies: toenail, hair and drinking water concentrations.

    PubMed

    Middleton, D R S; Watts, M J; Hamilton, E M; Fletcher, T; Leonardi, G S; Close, R M; Exley, K S; Crabbe, H; Polya, D A

    2016-05-18

    Chronic exposure to arsenic (As) in drinking water is an established cause of cancer and other adverse health effects. Arsenic concentrations >10 μg L(-1) were previously measured in 5% of private water supplies (PWS) in Cornwall, UK. The present study investigated prolongued exposure to As by measuring biomarkers in hair and toenail samples from 212 volunteers and repeated measurements of As in drinking water from 127 households served by PWS. Strong positive Pearson correlations (rp = 0.95) indicated stability of water As concentrations over the time period investigated (up to 31 months). Drinking water As concentrations were positively correlated with toenail (rp = 0.53) and hair (rp = 0.38) As concentrations - indicative of prolonged exposure. Analysis of washing procedure solutions provided strong evidence of the effective removal of exogenous As from toenail samples. Significantly higher As concentrations were measured in hair samples from males and smokers and As concentrations in toenails were negatively associated with age. A positive association between seafood consumption and toenail As and a negative association between home-grown vegetable consumption and hair As was observed for volunteers exposed to <1 As μg L(-1) in drinking water. These findings have important implications regarding the interpretation of toenail and hair biomarkers. Substantial variation in biomarker As concentrations remained unaccounted for, with soil and dust exposure as possible explanations. PMID:27120003

  8. Prolonged exposure to arsenic in UK private water supplies: toenail, hair and drinking water concentrations.

    PubMed

    Middleton, D R S; Watts, M J; Hamilton, E M; Fletcher, T; Leonardi, G S; Close, R M; Exley, K S; Crabbe, H; Polya, D A

    2016-05-18

    Chronic exposure to arsenic (As) in drinking water is an established cause of cancer and other adverse health effects. Arsenic concentrations >10 μg L(-1) were previously measured in 5% of private water supplies (PWS) in Cornwall, UK. The present study investigated prolongued exposure to As by measuring biomarkers in hair and toenail samples from 212 volunteers and repeated measurements of As in drinking water from 127 households served by PWS. Strong positive Pearson correlations (rp = 0.95) indicated stability of water As concentrations over the time period investigated (up to 31 months). Drinking water As concentrations were positively correlated with toenail (rp = 0.53) and hair (rp = 0.38) As concentrations - indicative of prolonged exposure. Analysis of washing procedure solutions provided strong evidence of the effective removal of exogenous As from toenail samples. Significantly higher As concentrations were measured in hair samples from males and smokers and As concentrations in toenails were negatively associated with age. A positive association between seafood consumption and toenail As and a negative association between home-grown vegetable consumption and hair As was observed for volunteers exposed to <1 As μg L(-1) in drinking water. These findings have important implications regarding the interpretation of toenail and hair biomarkers. Substantial variation in biomarker As concentrations remained unaccounted for, with soil and dust exposure as possible explanations.

  9. The physiological consequences of varied heat exposure events in adult Myzus persicae: a single prolonged exposure compared to repeated shorter exposures.

    PubMed

    Ghaedi, Behnaz; Andrew, Nigel R

    2016-01-01

    The study of environmental stress tolerance in aphids has primarily been at low temperatures. In these cases, and in the rare cases of high temperature tolerance assessments, all exposures had been during a single stress event. In the present study, we examined the physiological consequences of repeated high temperature exposure with recovery periods between these stress events in Myzus persicae. We subjected individuals to either a single prolonged three hour heating event, or three one hour heating events with a recovery time of 24 h between bouts. Aphids exposed to repeated bouts of high temperatures had more glucose and higher expression of proteins and osmolyte compounds, such as glycerol, compared to the prolonged exposure group. However, aphids exposed to the repeated high temperature treatment had reduced sources of energy such as trehalose and triglyceride compounds than the prolonged exposure group. Recovery time had more physiological costs (based on production of more protein and consumption of more trehalose and triglyceride) and benefits (based on production of more osmolytes) in repeated high temperature treatments. As aphids are known to respond differently to constant versus 'natural' fluctuating temperature regimes, conclusions drawn from constant temperature data sets may be problematic. We suggest future experiments assessing insect responses to thermal stress incorporate a repeated stress and recovery pattern into their methodologies. PMID:27547583

  10. The physiological consequences of varied heat exposure events in adult Myzus persicae: a single prolonged exposure compared to repeated shorter exposures.

    PubMed

    Ghaedi, Behnaz; Andrew, Nigel R

    2016-01-01

    The study of environmental stress tolerance in aphids has primarily been at low temperatures. In these cases, and in the rare cases of high temperature tolerance assessments, all exposures had been during a single stress event. In the present study, we examined the physiological consequences of repeated high temperature exposure with recovery periods between these stress events in Myzus persicae. We subjected individuals to either a single prolonged three hour heating event, or three one hour heating events with a recovery time of 24 h between bouts. Aphids exposed to repeated bouts of high temperatures had more glucose and higher expression of proteins and osmolyte compounds, such as glycerol, compared to the prolonged exposure group. However, aphids exposed to the repeated high temperature treatment had reduced sources of energy such as trehalose and triglyceride compounds than the prolonged exposure group. Recovery time had more physiological costs (based on production of more protein and consumption of more trehalose and triglyceride) and benefits (based on production of more osmolytes) in repeated high temperature treatments. As aphids are known to respond differently to constant versus 'natural' fluctuating temperature regimes, conclusions drawn from constant temperature data sets may be problematic. We suggest future experiments assessing insect responses to thermal stress incorporate a repeated stress and recovery pattern into their methodologies.

  11. The physiological consequences of varied heat exposure events in adult Myzus persicae: a single prolonged exposure compared to repeated shorter exposures

    PubMed Central

    Andrew, Nigel R.

    2016-01-01

    The study of environmental stress tolerance in aphids has primarily been at low temperatures. In these cases, and in the rare cases of high temperature tolerance assessments, all exposures had been during a single stress event. In the present study, we examined the physiological consequences of repeated high temperature exposure with recovery periods between these stress events in Myzus persicae. We subjected individuals to either a single prolonged three hour heating event, or three one hour heating events with a recovery time of 24 h between bouts. Aphids exposed to repeated bouts of high temperatures had more glucose and higher expression of proteins and osmolyte compounds, such as glycerol, compared to the prolonged exposure group. However, aphids exposed to the repeated high temperature treatment had reduced sources of energy such as trehalose and triglyceride compounds than the prolonged exposure group. Recovery time had more physiological costs (based on production of more protein and consumption of more trehalose and triglyceride) and benefits (based on production of more osmolytes) in repeated high temperature treatments. As aphids are known to respond differently to constant versus ‘natural’ fluctuating temperature regimes, conclusions drawn from constant temperature data sets may be problematic. We suggest future experiments assessing insect responses to thermal stress incorporate a repeated stress and recovery pattern into their methodologies. PMID:27547583

  12. Alveolar macrophage-stimulated neutrophil and monocyte migration: effects of in vitro ozone exposure

    SciTech Connect

    Driscoll, K.E.; Schlesinger, R.B.

    1988-04-01

    The ability of rabbit alveolar macrophages (AM) to release factors which stimulate the migration of peripheral blood neutrophils and monocytes was examined, and the influence of in vitro ozone exposure on this secretory activity was investigated. To evaluate the ability of AM to release leukocyte chemotactic activity, AM obtained by bronchoalveolar lavage were established in monolayer or suspension culture, with and without added zymosan, for 2 and 6 hr. The resulting macrophage-conditioned medium was tested for chemotactic activity using modified Boyden-type chambers and rabbit peripheral blood neutrophils or monocytes as the responding cells. The results demonstrate that substrate attachment (monolayer culture) and/or zymosan phagocytosis can stimulate AM to release chemoattractants for monocytes and neutrophils. Additionally, the results suggest that AM are constitutively producing low levels of monocyte chemotactic factors. The effects of in vitro ozone exposure on the secretion of chemotactic activity was investigated by exposing monolayer cultures of AM to air, 0.1, 0.3, or 1.2 ppm ozone for 2 hr. Macrophage-conditioned medium was harvested immediately, 2 and 6 hr postexposure, and tested for chemotactic activity. Exposure to 0.3 and 1.2 ppm ozone significantly increased the AM secretion of factors which stimulated neutrophil migration; additionally, the results strongly suggest that ozone can augment the ability of AM to stimulate monocyte migration. These results imply a role for the AM in the recruitment of inflammatory cells after ozone inhalation.

  13. Evaluation of the use of empirical ambient ozone pollutant modeling and subject activity logs as an indirect measurement of ozone exposure

    SciTech Connect

    Hopkins, L.P.; Fraser, M.P.; Ensor, K.B.; Rifai, H.S.

    1998-12-31

    The personal ozone exposure of women on the track team at Rice University was monitored using Harvard passive samplers over a period of six weeks during August and September of 1997. Each subject logged their location and activity in and around campus during the exposure period. A three-dimensional kriging model of ozone was developed to estimate the ozone exposure for each subject from ambient fixed site monitoring data. The ozone predictions from the model were combined with the activity and location information, adjusted for indoor environment when applicable, to estimate personal exposure concentrations for each subject. Using two independent approaches, the kriging model was proven to provide accurate spatial and temporal estimates of ozone at subject exposure points. The results from this work show that the method developed to estimate exposure through kriging over (x,y,t) to predict ozone concentrations at exposure points combined with subject activity/time logs produces exposure estimates within the error bounds of the analytical methods for personal monitoring.

  14. [Prolonged exposure to atmospheric air pollution and mortality from respiratory causes].

    PubMed

    Eilstein, D

    2009-12-01

    Different designs can be used to analyze the relationships between respiratory mortality and long term exposure to atmospheric pollution: epidemiological studies (cohort, prevalence study) demonstrate the reality of the relationship and toxicological studies explain it. Cohort studies have the advantage of being able to take into account many confounding factors and thus avoid biases (which is not the case with prevalence studies), but require significant human and financial resources. They were first adopted in the US, but are now more often applied in Europe. The results are relatively consistent, as they all show a statistically significant association between an increase in particulate pollution and cardiopulmonary mortality. Mortality from lung cancer is also associated with long term exposition to particles and sometimes to ozone or nitrogen oxides. Cerebrovascular diseases and sudden death of young children have also been associated with particulate pollution. The relationships are more powerful for long term than short term exposure but are also linear and without threshold. In order to explain these effects (today the causality of the relationship is certain) there are many possible factors, particularly regarding particulate exposures: an increase in cardiovascular risk biomarkers (fibrinogen, white blood cells, and platelets), atherosclerosis, chronic inflammation of lung tissues increased by acute exposure, etc. More and more studies address the interaction between gene and environment and even epigenetic phenomena which could be responsible of these effects. Public Health impact could be quantified. The European E&H surveillance program Apheis, for example, estimated that if PM2.5 levels remained below 15 microg/m(3), a 30 year old person could see his life expectancy increased by 1 month to 2 years, depending on the studied city. Finally, mortality is not the only relevant indicator for health effects of air pollution. ISAAC studies address asthma

  15. Long-term behavioral effects in a rat model of prolonged postnatal morphine exposure.

    PubMed

    Craig, Michael M; Bajic, Dusica

    2015-10-01

    Prolonged morphine treatment in neonatal pediatric populations is associated with a high incidence of opioid tolerance and dependence. Despite the clinical relevance of this problem, our knowledge of long-term consequences is sparse. The main objective of this study was to investigate whether prolonged morphine administration in a neonatal rat is associated with long-term behavioral changes in adulthood. Newborn animals received either morphine (10 mg/kg) or equal volume of saline subcutaneously twice daily for the first 2 weeks of life. Morphine-treated animals underwent 10 days of morphine weaning to reduce the potential for observable physical signs of withdrawal. Animals were subjected to nonstressful testing (locomotor activity recording and a novel-object recognition test) at a young age (Postnatal Days [PDs] 27-31) or later in adulthood (PDs 55-56), as well as stressful testing (calibrated forceps test, hot plate test, and forced swim test) only in adulthood. Analysis revealed that prolonged neonatal morphine exposure resulted in decreased thermal but not mechanical threshold. Importantly, no differences were found for total locomotor activity (proxy of drug reward/reinforcement behavior), individual forced swim test behaviors (proxy of affective processing), or novel-object recognition test. Performance on the novel-object recognition test was compromised in the morphine-treated group at the young age, but the effect disappeared in adulthood. These novel results provide insight into the long-term consequences of opioid treatment during an early developmental period and suggest long-term neuroplastic differences in sensory processing related to thermal stimuli.

  16. LONG-TERM BEHAVIORAL EFFECTS IN A RAT MODEL OF PROLONGED POSTNATAL MORPHINE EXPOSURE

    PubMed Central

    Craig, Michael M.; Bajic, Dusica

    2015-01-01

    Prolonged morphine treatment in neonatal pediatric populations is associated with a high incidence of opioid tolerance and dependence. Despite the clinical relevance of this problem, our knowledge of the long-term consequences is sparse. The main objective of this study was to investigate whether prolonged morphine administration in a neonatal rat is associated with long-term behavioral changes in adulthood. Newborn animals received either morphine (10mg/kg) or equal volume of saline subcutaneously twice daily for the first 2 weeks of life. Morphine treated animals underwent 10 days of morphine weaning to reduce the potential for observable physical signs of withdrawal. Animals were subjected to non-stressful testing (locomotor activity recording and a Novel-Object Recognition test) at a young age (PD27-31) or later in adulthood (PD55-56), as well as stressful testing (calibrated forceps test, Hot Plate test, and Forced Swim test) only in adulthood. Analysis revealed that prolonged neonatal morphine exposure resulted in decreased thermal, but not mechanical threshold. Importantly, no differences were found for total locomotor activity (proxy of drug reward/reinforcement behavior), individual Forced Swim test behaviors (proxy of affective processing), or Novel-Object Recognition test. Performance on the Novel-Object Recognition test was compromised in the morphine treated group at the young age, however the effect disappeared in adulthood. These novel results provide insight into the long-term consequences of opioid treatment during an early developmental period and suggest long-term neuroplastic differences in sensory processing related to thermal stimuli. PMID:26214209

  17. In vitro ozone exposure inhibits mitogen-induced lymphocyte proliferation and IL-2 production

    SciTech Connect

    Becker, S.; Jordan, R.L.; Orlando, G.S.; Koren, H.S.

    1989-01-01

    Human blood mononuclear cells were exposed to ozone in vitro and thereafter analyzed for competence in mitogen-induced proliferation as well as IL-1 and IL-2 production. Proliferative responses induced by phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) were all depressed in lymphocytes exposed to an ozone concentration of 1 ppm for 4-6 h. The response to PWM was most sensitive to the ozone effect (38% suppression); responses to Con A and PHA were suppressed to a lesser extent, 23% and 18%, respectively, and were not significantly different from each other. PWM responses were affected at an ozone concentration as low as 0.1 ppm; however, no suppression of Con A-induced proliferation was seen below 0.18 ppm or of PHA-induced proliferation below 0.5 ppm. When lymphocytes and monocytes were exposed separately to ozone and then mixed back with control air-exposed monocytes or lymphocytes, both cell types appeared to be affected and the functional defects caused by the pollutant were additive. Monocyte IL-1 production induced by endotoxin was not affected by ozone exposure, while surface expression of HLA-DR on exposed monocytes was reduced by 40% 24 h after exposure. Moreover, lymphocytes exposed to ozone produced 46% less IL-2 while expressing similar surface density of IL-2 receptors. Taken together, these results show that exposure to ozone has distinct adverse effects on lymphocytes and monocytes, both of which are important in local immune defenses in the lung.

  18. Hypothalamic sensing of ketone bodies after prolonged cerebral exposure leads to metabolic control dysregulation

    PubMed Central

    Carneiro, Lionel; Geller, Sarah; Hébert, Audrey; Repond, Cendrine; Fioramonti, Xavier; Leloup, Corinne; Pellerin, Luc

    2016-01-01

    Ketone bodies have been shown to transiently stimulate food intake and modify energy homeostasis regulatory systems following cerebral infusion for a moderate period of time (<6 hours). As ketone bodies are usually enhanced during episodes of fasting, this effect might correspond to a physiological regulation. In contrast, ketone bodies levels remain elevated for prolonged periods during obesity, and thus could play an important role in the development of this pathology. In order to understand this transition, ketone bodies were infused through a catheter inserted in the carotid to directly stimulate the brain for a period of 24 hours. Food ingested and blood circulating parameters involved in metabolic control as well as glucose homeostasis were determined. Results show that ketone bodies infusion for 24 hours increased food intake associated with a stimulation of hypothalamic orexigenic neuropeptides. Moreover, insulinemia was increased and caused a decrease in glucose production despite an increased resistance to insulin. The present study confirms that ketone bodies reaching the brain stimulates food intake. Moreover, we provide evidence that a prolonged hyperketonemia leads to a dysregulation of energy homeostasis control mechanisms. Finally, this study shows that brain exposure to ketone bodies alters insulin signaling and consequently glucose homeostasis. PMID:27708432

  19. Changes in Temporal Attention Inhibition Following Prolonged Exposure and Sertraline in the Treatment of PTSD

    PubMed Central

    Echiverri-Cohen, Aileen; Zoellner, Lori A.; Gallop, Robert; Feeny, Norah; Jaeger, Jeffrey; Bedard-Gilligan, Michele

    2016-01-01

    Objective Attentional inhibitory deficits expressed as difficulty ignoring irrelevant stimuli in the pursuit of goal-directed behavior may serve as a fundamental mechanism of posttraumatic stress disorder (PTSD). Evidence of inhibitory processes as central to extinction suggests that exposure-based treatments may act more directly on the inhibitory deficits implicated in PTSD, whereas, in facilitating serotonergic neurotransmission, selective serotonin reuptake inhibitors (SSRIs) may be less direct and bring about general neurochemical changes in the fear circuitry. If these inhibitory deficits underlie PTSD, then inhibition should improve with successful treatment, with those treated with prolonged exposure (PE) potentially resulting in greater changes in inhibition than those treated with sertraline. Method Changes in temporal attentional inhibition, using an attentional blink (AB) paradigm, were examined at pre-and post-treatment in 49 individuals (74.5% female, 66.7% Caucasian, age M = 37.69, SD = 12.8 years) with chronic PTSD. Participants completed 10 weeks of either PE or sertraline. Results Individuals who made greater improvements with PE showed faster improvements in temporal inhibition on the critical inhibitory lag of AB than those who made greater improvements with sertraline (d = 0.94). These changes could not be accounted for by basic attention. Conclusions Greater improvement in fundamental attentional inhibitory processes with better treatment response to PE, compared to sertraline, suggests potential specificity in how PTSD treatments normalize inhibitory processes, such that exposure-based treatments like PE may target inhibitory processes and improve basic inhibitory functioning. Public Health Significance Statement Inhibitory processes, particularly related to temporal attention, may play a critical role in response to exposure therapy for PTSD. The main finding that individuals with PTSD who made more clinical improvement showed faster

  20. Adolescent pre-exposure to ethanol or MDMA prolongs the conditioned rewarding effects of MDMA.

    PubMed

    Do Couto, B Ribeiro; Rodríguez-Arias, M; Fuentes, S; Gagliano, H; Armario, A; Miñarro, J; Aguilar, M A

    2011-07-01

    Adolescents often take ethanol (EtOH) in combination with MDMA (3,4-methylenedioxymethylamphetamine). In the present work we studied the effect of repeated intermittent adolescent pre-exposure to both drugs on the behavioral and neurochemical effects of MDMA in mice. Sixteen days after pre-treatment, the rewarding and reinstating effects of MDMA in the conditioned place preference (CPP) paradigm were evaluated, along with the levels of biogenic amines, basal motor activity and corticosterone response to different challenges. Pre-exposure to EtOH, MDMA or EtOH+MDMA did not affect the CPP induced by 10mg/kg of MDMA. However, adolescent exposure to EtOH or MDMA increased the duration of the conditioned rewarding effects of MDMA. Following extinction of the CPP, a priming dose of 5mg/kg of MDMA elicited reinstatement in all the groups, with the duration of this reinstated CPP being longer in mice pre-treated with MDMA. After reinstatement, an increase in monoamine levels was observed in mice pre-exposed to EtOH (DA, DOPAC and 5-HT in the striatum and 5-HIAA in the cortex and hippocampus) or MDMA (5-HT in the hippocampus). Basal motor activity and basal levels of corticosterone were not affected by any of these pre-treatments, but the group pre-exposed to MDMA showed higher levels of corticosterone in response to the administration of 10mg/kg of MDMA. Behavioral and hormonal effects of adolescent exposure to MDMA were reversed by co-administration of EtOH. Our results suggest that exposure to EtOH or MDMA during adolescence prolongs the rewarding properties of MDMA.

  1. Does Change in Distress Matter? Mechanisms of Change in Prolonged Exposure for PTSD

    PubMed Central

    Bluett, Ellen J.; Zoellner, Lori A.; Feeny, Norah C.

    2013-01-01

    Background and Objectives Clinically, many individuals persist in prolonged exposure therapy (PE) for chronic PTSD despite continuing distress during recounting of the trauma memory (imaginal exposure). Theorists suggest that distress reduction is necessary for successful treatment outcome (e.g., Foa & Kozak, 1986), while others suggest otherwise (e.g., Craske et al., 2008). This study examined clinically reliable changes in distress, relations to broad clinical outcomes, and whether homework adherence affected this relationship. Method In 116 patients with PTSD, first to last imaginal exposure sessions’ peak and average distress was examined, calculating reliable change in distress. Homework adherence and helpfulness were examined. At post-treatment, PTSD symptoms (re-experiencing, avoidance, hyperarousal), depression, and functioning were examined. Results Patients exhibited a lack of reliable change in distress (64.7%) more than a reliable change in distress (35.3%). Although no difference in post-treatment PTSD diagnostic status, individuals experiencing a reliable change in distress reported lower PTSD severity (re-experiencing, hyperarousal), depression, and better functioning. Further, perceived helpfulness of imaginal homework had an indirect effect on this relationship. Limitations This study did not utilize a distress tolerance self-report measure; however, examined self-reported distress during imaginal exposure. Conclusions Results are encouraging for clinicians treating PTSD with PE, arguing that lack of reliable change in distress to the trauma memory does not result in treatment failure. Patient “buy in” to homework, rather than amount completed, was related to the process of distress reduction. Results suggest that distress reduction in imaginal exposure is not a key mechanism underlying therapeutic change in PE. PMID:24091202

  2. Prolonged exposure of the HIV-1 gp41 membrane proximal region with L669S substitution

    PubMed Central

    Shen, Xiaoying; Dennison, S. Moses; Liu, Pinghuang; Gao, Feng; Jaeger, Frederick; Montefiori, David C.; Verkoczy, Laurent; Haynes, Barton F.; Alam, S. Munir; Tomaras, Georgia D.

    2010-01-01

    The conserved membrane-proximal external region (MPER) of HIV-1 envelope is a target for the rare broadly neutralizing 2F5, Z13, and 4E10 monoclonal antibodies (mAbs). One strategy to elicit such antibodies is to design an immunogen with increased exposure of the 2F5 and 4E10 mAb epitopes. In this study we characterize a single leucine to serine substitution at position 669 (L669S) in the gp41 Env MPER that confers >250-fold more neutralization sensitivity to 2F5 and 4E10 mAbs than does the wild-type gp41 sequence. On synthetic liposomes, increased solvent exposure of MPER tryptophan residues and stable docking of 2F5 and 4E10 mAbs to mutant MPER peptide liposomes indicate more favorable membrane orientation of MPER neutralizing epitopes with L669S substitution. The time during which virus is sensitive to 2F5 mAb-mediated neutralization is approximately 3-fold longer when the mutation is present. These data suggest that a major contribution to the L669S mutant virus phenotype of enhanced susceptibility to MPER mAbs is prolonged exposure of the MPER neutralizing epitope during viral entry. PMID:20231447

  3. Signal transduction disturbance related to hepatocarcinogenesis in mouse by prolonged exposure to Nanjing drinking water.

    PubMed

    Zhang, Rui; Sun, Jie; Zhang, Yan; Cheng, Shupei; Zhang, Xiaowei

    2013-09-01

    Toxicogenomic approaches were used to investigate the potential hepatocarcinogenic effects on mice by oral exposure to Nanjing drinking water (NJDW). Changes in the hepatic transcriptome of 3 weeks male mice (Mus musculus) were monitored and dissected after oral exposure to NJDW for 90 days. No preneoplastic and neoplastic lesions were observed in the hepatic tissue by the end of NJDW exposure. However, total of 746 genes were changed transcriptionally. Thirty-one percent of differentially expressed genes (DEGs) were associated with the functional categories of cell cycle regulation, adhesion, growth, apoptosis, and signal transduction, which are closely implicated in tumorigenesis and progression. Interrogation of Kyoto Encyclopedia of Genes and Genomes revealed that 43 DEGs were mapped to several crucial signaling pathways implicated in the pathogenesis of hepatocellular carcinoma (HCC). In signal transduction network constructed via Genes2Networks software, Egfr, Akt1, Atf2, Ctnnb1, Hras, Mapk1, Smad2, and Ccnd1 were hubs. Direct gene-disease relationships obtained from Comparative Toxicogenomics Database and scientific literatures revealed that the hubs have direct mechanism or biomarker relationships with hepatocellular preneoplastic lesions or hepatocarcinogenesis. Therefore, prolonged intake of NJDW without employing any indoor water treatment strategy might predispose mouse to HCC. Furthermore, Egfr, Akt1, Ctnnb1, Hras, Mapk1, Smad2, and Ccnd1 were identified as promising biomarkers of the potential combined hepatocarcinogenicity.

  4. OZONE AND NATURAL SYSTEMS: UNDERSTANDING EXPOSURE, RESPONSE, AND RISK

    EPA Science Inventory

    Research aimed at understanding the response of plants to ozone has been conducted for over four decades but little of it has addressed intact natural systems. Even so, there is sufficient information at this time to establish air quality standards that will protect natural terr...

  5. Experimental chronic obstructive lung disease. I. Bronchopulmonary changes induced in rabbits by prolonged exposure to formaldehyde.

    PubMed

    Ionescu, J; Marinescu, D; Tapu, V; Eskenasy, A

    1978-01-01

    The prolonged exposure to formaldehyde induces in the rabbit lung reactional and dystrophic changes involving the intrapulmonary bronchi, the bronchioli and the lung tissue. These changes are represented by bronchial cell hyperplasia with hypermucigenesis, extrusion of bronchial cells, bronchiolar hypermucigenesis, parcellary squamous metaplasia or necrobiosis of epithelia, thickening of bronchial and bronchiolar walls by subepithelial cell accumulations, destruction of musculo-elastic structures with stenosis or ectasia; the vascular reactions are hyperhaemic and proliferative with an obstructive and fibrous tendency; the parenchymal lesions are atelectasias, intralobular emphysema, and cellular thickening of alveolar walls and interlobular areas. The acid phosphatase, Tween-60-esterase, naphthol-AS-D-acetate-esterase, proline-oxidase and hydroxyproline-2-epimerase activities are increasing, while the leucyl-aminopeptidase and beta-glucuronidase ones are decreasing. The qualitative observations are completed and sustained by quanitative studies of mucous cell kinetics, of cell accumulations and differentiations. PMID:151223

  6. Effects of additional prolonged exposure to psychoeducation and relaxation in acute stress disorder.

    PubMed

    Freyth, Claudia; Elsesser, Karin; Lohrmann, Thomas; Sartory, Gudrun

    2010-12-01

    We investigated the effect of prolonged exposure (PE) on the heart rate (HR) and skin conductance response to trauma-related stimuli in acute stress disorder (ASD). Forty recent trauma victims with ASD were randomly assigned to three sessions of either PE or supportive counseling (SC) with both groups also receiving psychoeducation and progressive relaxation. Assessments were carried out before and after treatment and again after 3 months. Four years later, patients were asked by telephone whether they had received further treatment. There were no significant group differences with regard to symptomatic improvement at the end of treatment. Both groups showed initial cardiac acceleration to trauma-related pictures. After treatment the PE group showed attenuation of the HR response and a reduction in spontaneous fluctuations (SF) whereas the SC group showed a decelerative (orienting) response and a marginal increase in SF. Following SC, 43% received further treatment compared to 9% after PE.

  7. Mild traumatic brain injury and treatment response in prolonged exposure for PTSD.

    PubMed

    Sripada, Rebecca K; Rauch, Sheila A M; Tuerk, Peter W; Smith, Erin; Defever, Andrew M; Mayer, Rebecca A; Messina, Michael; Venners, Margaret

    2013-06-01

    A proportion of U.S. veterans returning from Iraq and Afghanistan have experienced mild traumatic brain injury (mTBI), which is associated with increased risk for developing posttraumatic stress disorder (PTSD). Prolonged Exposure (PE) has proven effectiveness in the treatment of PTSD; however, some clinicians have reservations about using PE with individuals with a history of mTBI. We examined the impact of PE for veterans with PTSD and with or without a history of mTBI in a naturalistic sample of 51 veterans who received PE at a Veterans Health Administration PTSD clinic. We also analyzed previously collected data from a controlled trial of 22 veterans randomly assigned to PE or present centered therapy. For both sets of data, we found that PE reduced symptom levels and we also did not detect an effect for mTBI, suggesting that PE may be helpful for individuals with PTSD and a history of mTBI. PMID:23696427

  8. Increased agonist affinity at the mu-opioid receptor induced by prolonged agonist exposure

    PubMed Central

    Birdsong, William T.; Arttamangkul, Seksiri; Clark, Mary J.; Cheng, Kejun; Rice, Kenner C.; Traynor, John R.; Williams, John T.

    2013-01-01

    Prolonged exposure to high-efficacy agonists results in desensitization of the mu opioid receptor (MOR). Desensitized receptors are thought to be unable to couple to G-proteins, preventing downstream signaling, however the changes to the receptor itself are not well characterized. In the current study, confocal imaging was used to determine whether desensitizing conditions cause a change in agonist-receptor interactions. Using rapid solution exchange, the binding kinetics of fluorescently labeled opioid agonist, dermorphin Alexa594 (derm A594), to MORs was measured in live cells. The affinity of derm A594 binding increased following prolonged treatment of cells with multiple agonists that are known to cause receptor desensitization. In contrast, binding of a fluorescent antagonist, naltrexamine Alexa 594, was unaffected by similar agonist pre-treatment. The increased affinity of derm A594 for the receptor was long-lived and partially reversed after a 45 min wash. Treatment of the cells with pertussis toxin did not alter the increase in affinity of the derm A594 for MOR. Likewise the affinity of derm A594 for MORs expressed in mouse embryonic fibroblasts derived from arrestin 1 and 2 knockout animals increased following treatment of the cells with the desensitization protocol. Thus, opioid receptors were “imprinted” with a memory of prior agonist exposure that was independent of G-protein activation or arrestin binding that altered subsequent agonist-receptor interactions. The increased affinity suggests that acute desensitization results in a long lasting but reversible conformational change in the receptor. PMID:23447620

  9. Exposure to ozone reduces postharvest quality loss in red and green chilli peppers.

    PubMed

    Glowacz, Marcin; Rees, Deborah

    2016-11-01

    The effect of continuous exposure to ozone at 0.45, 0.9 and 2μmolmol(-1) on quality changes during the storage of red and green chilli peppers at 10°C was investigated. Ozone at 0.45 and 0.9μmolmol(-1) reduced disease incidence in red peppers, with no further benefits at 2μmolmol(-1). Ozone at 0.9μmolmol(-1) reduced weight loss during storage and improved firmness maintenance. Skin colour was bleached in red peppers exposed to ozone at 2μmolmol(-1), and in green ones at all tested doses. Total phenolic content was not affected by ozone but antioxidant activity was reduced in green chilli peppers exposed to ozone at 2μmolmol(-1), due to lower ascorbic acid content in those samples. Ozone at 0.9μmolmol(-1) extended the shelf-life of chilli peppers. PMID:27211651

  10. Preliminary assessment of human exposure to ozone in Mexico City using a GIS-based methodology

    SciTech Connect

    Cicero-Fernandez, P.; Winer, A.M.; Otero-Delgado, A.; Sanchez-Martinez, S.

    1998-12-31

    The main goal of this study was to evaluate the magnitude of ozone exposure experienced by the population of a large metropolitan zone encompassing Mexico City. Demographic geocoded databases from the Mexican National Institute of Statistics, Geography and Information were acquired and analyzed to develop the required population spatial distributions. With the use of a geographic information system (GIS), and other statistical tools, it was possible to generate spatially- and temporally-resolved ozone distributions for indoor and outdoor microenvironments. The ozone levels were determined using various air quality metrics to assess extreme and average exposures for the demographic groups. Populations with the most time spent outdoors at high ozone concentration locations experienced ozone above the Mexican air quality standard as much as 80% of the days of the year, and more than one thousand hours annually. Co-located populations entirely indoors potentially experienced ozone above the Mexican air quality standard 16% of the days of the year, and more than one hundred hours annually. The basic methodology described in this paper integrates both demographic and air quality geocoded databases, allowing the evaluation of various air pollution scenarios. For the particular case of Mexico City, this methodology is starting to be used as a tool to support epidemiological surveillance and, during extreme episodes, to identify and implement mitigation actions

  11. Effect of ozone exposure on antigen-induced airway hyperresponsiveness in guinea pigs

    SciTech Connect

    Vargas, M.H.; Segura, P.; Campos, M.G.; Hong, E.; Montano, L.M.

    1994-12-31

    Airway hyperresponsiveness can be induced by several stimuli including antigen and ozone, both of which may be present in the air of polluted cities. Though the effect of ozone on the bronchoconstrictor response to antigen has been well described, the combined effect of these stimuli on airway hyperresponsiveness has not yet been studied. Sensitized guinea pigs with or without ozone exposure for 1 h at 3 ppm, 18 h prior to study, were challenged with a dose-response curve to histamine (0.01-1.8 {mu}g/kg, iv), and then by a second histamine dose-response curve 1 h later. Airway responses were measured as the increase in pulmonary insufflation pressure. In sensitized guinea pigs, the histamine ED50 significantly decreased after antigen challenge, demonstrating the development of airway hyperresponsiveness. Sensitized guinea pigs exposed to ozone showed airway hyperresponsiveness to histamine when compared with nonexposed animals, and such hyperresponsiveness was further enhanced after antigen challenge. We conclude that in this guinea pig model of acute allergic bronchoconstriction both antigen challenge and ozone induce airway hyperresponsiveness, while ozone exposure does not modify the development of antigen-induced hyperresponsiveness. 25 refs., 1 fig., 1 tab.

  12. US Environmental Protection Agency's ozone epidemiology research program: A strategy for assessing the effects of ambient ozone exposure upon morbidity in exposed populations

    SciTech Connect

    McDonnell, W.F.; Zenick, H.; Hayes, C.G.

    1993-01-01

    The Clean Air Act Amendments of 1990 mandate a future reduction of ambient ozone levels in many areas of the country, the cost of which will be great. In order to assess the current public health burden of ambient ozone exposure and to provide information for assessment of potential health benefits of improved air quality, the Health Effects Research Laboratory of the U.S. EPA has undertaken an Ozone Epidemiology Research Program. The three questions identified as being of most immediate importance involve the relationship of short-term ambient ozone exposure to acute respiratory illness, the relationship of recurrent exposure to chronic respiratory disease, and the relationship of recurrent exposure to development of acute respiratory illness. (Copyright (c) 1993 Air and Waste Management Association.)

  13. The action spectrum for vitamin D3: initial skin reaction and prolonged exposure.

    PubMed

    van Dijk, Arjan; den Outer, Peter; van Kranen, Henk; Slaper, Harry

    2016-07-01

    Vitamin D3 photosynthesis in the skin is formulated as a set of reaction equations, including side-reactions to lumisterol, tachysterol and toxisterols, and the accompanying reverse reactions, isomerisation of previtamin D3 to vitamin D3 and photodegradation of vitamin D3. The solution of this set is given for the stationary irradiance spectrum. The effective action spectrum for the instantaneous vitamin D3 production changes shape as a function of exposure, and therefore, no single action spectrum can be used. We assessed the action spectrum for unexposed skin and for skin that has been exposed to 7.5 Standard Erythemal Doses (SED). We constructed two new estimates: (1) the RIVM action spectrum, based on absorption spectra, quantum yields and skin transmission spectra, and (2) the modified QUT action spectrum, which is adjusted for self-absorption and skin transmission. For previously unexposed skin, the modified QUT action spectrum gives a qualitatively similar, but larger estimate than the RIVM action spectrum. We have not been able to solve the lack of quantitative agreement between the vitamin D production estimates from the three action spectrum estimates (RIVM, modified QUT and CIE). All new action spectra have stronger emphasis on the short wavelengths than the CIE action spectrum. We showed that, for wavelengths larger than 300 nm, the bandwidth that was used in the experiment that formed the basis of the CIE action spectrum, gives a red-shift of about 1 nm. Generally, with the formation of previtamin D3, the return reaction to provitamin D3 limits the production of vitamin D3. After some exposure, the new action spectrum has negative values for the longer wavelengths in the UVB. For the RIVM action spectrum, this happens after 7.5 SED, for the modified QUT action spectrum already after 1.25 SED, and after 7.5 SED the net production rate is largely cancelled. Thus prolonged exposure of previously unexposed skin saturates vitamin D3 formation. For maximum

  14. Relationships between ozone exposure and yield loss in European wheat and potato—a comparison of concentration- and flux-based exposure indices

    NASA Astrophysics Data System (ADS)

    Pleijel, H.; Danielsson, H.; Ojanperä, K.; Temmerman, L. De; Högy, P.; Badiani, M.; Karlsson, P. E.

    Data from open-top chamber experiments with field grown crops, performed in Sweden, Finland, Belgium, Italy and Germany, were combined to derive relationships between yield and ozone exposure for wheat ( Triticum aestivum L.) and potato ( Solanum tuberosum L.). Three different exposure indices were compared: AOT40 (accumulated exposure over a threshold ozone concentration of 40 nmol mol -1), CUO t (cumulative stomatal uptake of ozone, using a constant ozone uptake rate threshold of t nmol m -2 s -1) and mAOT c0 (conductance modified AOT using a threshold concentration for ozone of c0 nmol mol -1). The latter is essentially a combination of AOT and CUO. Ozone uptake was estimated using a Jarvis-type multiplicative model for stomatal conductance. In terms of correlation between relative yield (RY) and ozone exposure, CUO 5, the CUO index with an ozone uptake rate threshold of 5 nmol m -2 s -1, performed best for both wheat and potato, resulting in r2 values of 0.77 and 0.64, respectively. CUO 5 performed considerably better in terms of the correlation between RY and ozone exposure, than AOT40 for wheat, while mAOT10, the best performing mAOT index in this case, was intermediate in performance for this crop. For potato, the differences between the different ozone exposure indices AOT40, CUO 5 and mAOT20 (the mAOT index performing best for potato) in the correlation between RY and ozone exposure were relatively small. To test the assumption that the non-stomatal deposition of ozone was negligible for the uppermost, sunlit leaves, measurements of ozone uptake in relation to leaf conductance for water vapor of wheat leaves in a cuvette system were used. The non-stomatal deposition of ozone to the leaves turned out to be comparatively small. Based on the non-stomatal conductance ( gns=15 mmol m -2 s -1) estimated for the wheat leaves in the cuvette system, it was concluded that the consequence of omitting the non-stomatal conductance is small. In conclusion the study

  15. Exposure of rats to ozone: evidence of damage to heart and brain

    SciTech Connect

    Rahman, I.; Massaro, G.D.; Massaro, D. )

    1992-01-01

    Ozone is a strong oxidizing agent, and in many locations it is a major atmospheric pollutant. It is phytotoxic and an important cause of lung dysfunction in humans. Recently, a significant association has been established between total atmospheric oxidants, of which ozone is one, and daily cardiovascular mortality rates. In this article, we show that exposure of rats to ozone for 5 days, in a concentration found in major urban centers, results in an increased concentration of thiobarbituric acid-reactive material (an indicator of lipid peroxidation) in heart and brain tissue as well as elevated activity of catalase and glutathione peroxidase (enzymic scavengers of peroxides) in these tissues. We examined the heart anatomically and found evidence of extracellular and intracellular edema. These findings indicate that the heart and brain are damaged by a concentration of ozone present in major urban centers; they may have important implications for chronic illness and degenerative processes in humans.

  16. Morphologic alteration of the olfactory bulb after acute ozone exposure in rats.

    PubMed

    Colín-Barenque, L; Avila-Costa, M R; Fortoul, T; Rugerio-Vargas, C; Machado-Salas, J P; Espinosa-Villanueva, J; Rivas-Arancibia, S

    1999-10-15

    The interaction of ozone with some molecules results in an increased production of free radicals. The objective of this study was to identify whether acute ozone exposure to 1-1.5 ppm for 4 h, produced cytological and ultrastructural modifications in the olfactory bulb cells. The results showed that in rats exposed to ozone there was a significant loss of dendritic spines on primary and secondary dendrites of granule cells, whereas the control rats did not present such changes. Besides these exposed cells showed vacuolation of neuronal cytoplasm, swelling of Golgi apparatus and mitochondrion, dilation cisterns of the rough endoplasmic reticulum. These findings suggest that oxidative stress produced by ozone induces alterations in the granule layer of the olfactory bulb, which may be related to functional modifications.

  17. Episodic ozone exposure in adult and Senescent Brown Norway rats: Acute and delayed cardiovascular and thermoregulatory responses

    EPA Science Inventory

    Setting exposure standards for environmental pollutants may consider the aged as a susceptible population but the few published studies assessing susceptibility of the aged to air pollutants are inconsistent. Episodic ozone (O(3)) is more reflective of potential exposures occurri...

  18. Consequences of prolonged inhalation of ozone on F344/N rats: collaborative studies. Part IV: Effects on expression of extracellular matrix genes.

    PubMed

    Parks, W C; Roby, J D

    1994-10-01

    Increased deposition of lung extracellular matrix in terminal airways is associated with chronic ozone exposure. In situ hybridization was used to assess whether long-term ozone exposure causes elevated and continued expression of genes coding for connective tissue proteins. Accessory lobes were removed from the animals exposed to 0, 0.12, 0.5, or 1.0 parts per million (ppm)* ozone for 20 months as part of the National Toxicology Program (NTP)/HEI Collaborative Ozone Project. The lungs were perfused fixed under physiologic pressure and processed for in situ hybridization. Sections were hybridized with 35S-labeled probes for messenger RNA (mRNA) coding for various matrix proteins, including collagen types I and III, elastin, and fibronectin, and for interstitial collagenase, a matrix metalloproteinase. Fetal rat lung was used as a positive control for hybridization. No signal for any mRNA was detected in terminal airway stromal cells of lungs from animals exposed to ozone for 20 months or control animals breathing clean air. In all samples from animals exposed to ozone for 20 months and control animals, only a very weak signal was seen in occasional cells within the interstitial spaces around large airways and blood vessels. In contrast, a strong signal for matrix-related mRNA was detected in fetal lung tissue. These findings indicate that active or enhanced matrix production is turned off in the adult animals used in the ozone studies, suggesting that the increase in matrix deposition results from a transient and early fibrotic response. Indeed, signal for type I procollagen and tropoelastin mRNAs was seen in alveolar septal cells in lungs of rats exposed to ozone for two months. No signal was seen in alveolar cells of age-matched control animals. (These animals, exposed for two months, and age-matched controls were from earlier studies supported by the HEI.) These findings indicate that ozone mediates a transient fibrotic response that results in a sustained

  19. A meta-analytic review of prolonged exposure for posttraumatic stress disorder.

    PubMed

    Powers, Mark B; Halpern, Jacqueline M; Ferenschak, Michael P; Gillihan, Seth J; Foa, Edna B

    2010-08-01

    Two decades of research demonstrate the efficacy of exposure therapy for posttraumatic stress disorder (PTSD). The efficacy of prolonged exposure (PE), a specific exposure therapy program for PTSD that has been disseminated throughout the world, has been established in many controlled studies using different trauma populations. However, a meta-analysis of the effectiveness of PE for PTSD has not been conducted to date. The purpose of the current paper is to estimate the overall efficacy of PE for PTSD relative to adequate controls. We included all published randomized controlled trials of PE vs. control (wait-list or psychological placebo) for the treatment of PTSD in adolescents or adults. Treatments were classified as PE if they included multiple sessions of imaginal and in vivo exposure and were based on the manualized treatment developed by Foa, Rothbaum, Riggs, and Murdock (1991). Thirteen studies with a total sample size of 675 participants met the final inclusion criteria. The primary analyses showed a large effect for PE versus control on both primary (Hedges's g=1.08) and secondary (Hedges's g=0.77) outcome measures. Analyses also revealed medium to large effect sizes for PE at follow-up, both for primary (Hedges's g=0.68) and secondary (Hedges's g=0.41) outcome measures. There was no significant difference between PE and other active treatments (CPT, EMDR, CT, and SIT). Effect sizes were not moderated by time since trauma, publication year, dose, study quality, or type of trauma. The average PE-treated patient fared better than 86% of patients in control conditions at post-treatment on PTSD measures. PE is a highly effective treatment for PTSD, resulting in substantial treatment gains that are maintained over time.

  20. Wet-cold exposure and hypothermia: thermal and metabolic responses to prolonged exercise in rain.

    PubMed

    Thompson, R L; Hayward, J S

    1996-09-01

    Simulated conditions of hiking in rain, wind, and cold, without protective rainwear, were used to investigate wet-cold hypothermia in 18 male subjects. Thermal, metabolic, and motor responses were monitored during an attempted 5-h walk (5.1 km/h) at 5 degrees C, with continuous exposure to rain (7.4 cm/h) and wind (8.0 km/h) over the final 4 h. The majority of subjects (11) could not complete the protocol because of intolerance of wet-cold conditions during the last 2 h. Therefore, data from 5 subjects who completed the protocol in rain and control conditions were used to describe the general pattern of response. During the 1st h of walking, core temperature rose 1 degree C to 38.1 degrees C. The subsequent 2 h of rain caused substantial cold stress, indicated by a 40% increase in heat production due to shivering and significant loss of strength and manual dexterity. However, core temperature only decreased to 37.1 degrees C, merely eliminating the initial exercise hyperthermia. Over the last 2 h of rain, core temperature remained relatively stable at 36.8 degrees C, decreasing slightly to 36.4 degrees C by 5 h. Two other subjects developed significant hypothermia (35 degrees C). One demonstrated fatigue of shivering after 2.5 h of rain, confirming the exhaustion hypothesis of wet-cold hypothermia. The older cooled rapidly when he failed to maintain the walking pace. We conclude that if a person can tolerate the intense discomfort of prolonged wet-cold exposure, he or she has the potential to resist significant core hypothermia for at least 4 h of walking under the conditions of this experiment. Exceptions to this generalization occur, making exposure of < 4 h a hypothermia risk for some individuals. Exposures > 4 h would involve increasing probability of rapid decline into hypothermia, associated with exhaustion of shivering and exercise heat production.

  1. Rat lung recovery from 3 days of continuous exposure to 0. 75 ppm ozone

    SciTech Connect

    Bassett, D.J.; Bowen-Kelly, E.; Elbon, C.L.; Reichenbaugh, S.S.

    1988-01-01

    The present study investigated the inflammatory responses and enzyme levels in lungs isolated from male Wistar rats after 3 d of continuous exposure to 0.75 ppm ozone and following 4 d of recovery in air. These times are associated with maximal proliferation of the alveolar type II epithelium and their subsequent transformation to new type I cells. Immediately following ozone exposure, bronchoalveolar lavage demonstrated neutrophil accumulation that was no longer present 4 d later. The number of lavaged macrophages was also found to be increased immediately following ozone exposure, and remained elevated at 4 d postexposure. Whole-lung determinations of key enzymes involved in energy generation (succinate oxidase) and maintenance of lung NADPH and reduced glutathione were corrected for changes in cell number, by use of lung DNA measurements. Immediately following ozone exposure succinate oxidase (SOX), glucose-6-phosphate (G6PD), and 6-phosphogluconate (6PGD) dehydrogenase activities per milligram DNA were significantly enhanced by 76%, 48%, and 21%, respectively. These data suggested that ozone-exposed lungs had cells with increased mitochondria and NADPH-generating capability consistent with the increased metabolic needs of a proliferating epithelium. At 4 d postexposure, only G6PD activity per milligram DNA remained higher by 22% than air-exposed controls. Although both glutathione reductase (GSSG-R) and peroxidase (GSH-Px) activities per lung were elevated in lungs immediately following exposure and 4 d later, when corrected for DNA only GSH-Px activity was significantly increased by 29% in lungs after the postexposure period. Lungs 4 d postexposure therefore had cells relatively enriched in G6PD and GSH-Px that might account for the increased ozone tolerance that has previously been associated with the formation of new type I epithelium.

  2. Effect of Gaseous Ozone Exposure on the Bacteria Counts and Oxidative Properties of Ground Hanwoo Beef at Refrigeration Temperature.

    PubMed

    Cho, Youngjae; Muhlisin; Choi, Ji Hye; Hahn, Tae-Wook; Lee, Sung Ki

    2014-01-01

    This study was designed to elucidate the effect of ozone exposure on the bacteria counts and oxidative properties of ground Hanwoo beef contaminated with Escherichia coli O157:H7 at refrigeration temperature. Ground beef was inoculated with 7 Log CFU/g of E. coli O157:H7 isolated from domestic pigs and was then subjected to ozone exposure (10×10(-6) kg O3 h(-1)) at 4℃ for 3 d. E. coli O157:H7, total aerobic and anaerobic bacterial growth and oxidative properties including instrumental color changes, TBARS, catalase (CAT) and glutathione peroxidase (GPx) activity were evaluated. Ozone exposure significantly prohibited (p<0.05) the growths of E. coli O157:H7, total aerobic and anaerobic bacteria in ground beef samples during storage. Ozone exposure reduced (p<0.05) the CIE a* value of samples over storage time. The CIE L* and CIE b* values of the samples fluctuated over storage time, and ozone had no clear effect. Ozone exposure increased the TBARS values during 1 to 3 d of storage (p<0.05). The CAT and GPx enzyme activities were not affected by ozone exposure until 2 and 3 d of storage, respectively. This study provides information about the use of ozone exposure as an antimicrobial agent for meat under refrigerated storage. The results of this study provide a foundation for the further application of ozone exposure by integrating an ozone generator inside a refrigerator. Further studies regarding the ozone concentrations and exposure times are needed. PMID:26761291

  3. Rat lung metabolism after 3 days of continuous exposure to 0. 6 ppm ozone

    SciTech Connect

    Bassett, D.J.; Bowen-Kelly, E.

    1986-02-01

    Continuous exposure of rats to low concentrations of ozone has previously been associated with enhanced metabolic enzyme activities, when measured in lung homogenates. In this study, metabolic rates were measured in intact perfused lungs with altered pathology brought about by 3 days continuous exposure to 0.6 ppm ozone. Increased metabolism of ozone-exposed lungs was indicated by a twofold enhancement in glucose utilization, associated with a 62% increase in lactate formation and a 166% increase in the rate of 14CO2 production from D-(U-14C)glucose from control values of 5.2 +/- 0.5 mumol lactate and 4.4 +/- 0.6 mumol 14CO2/h per lung (+/- SE, n = 4), respectively. Mitochondrial metabolism was separately assessed by measurements of 14CO2 production from (U-14C)-pyruvate, which was found not to be significantly altered by ozone exposure, although homogenate oxygen uptake in the presence of succinate was significantly enhanced by 57%. These changes in intermediary metabolism could be correlated with increased glucose carbon incorporation into lipid and elevated activity of glucose-6-phosphate dehydrogenase. The observed elevated metabolic rates were consistent with the energy and synthetic needs of a lung during repair of ozone-induced damage.

  4. Reduction of influenza virus pathogenesis by exposure to 0. 5 ppm ozone

    SciTech Connect

    Jakab, G.J.; Hmieleski, R.R.

    1988-01-01

    Continuous exposure to 0.5 ppm ozone during the course of murine influenza A/PR8/34 virus infection reduced the severity of the disease as quantitated by histologic (morphometric), biochemical (serum albumin in lavage fluid), and gravimetric (lung wt/dry weight ratios) parameters of lung injury. The ozone-mediated abatement of the lung injury was independent of peak pulmonary virus titers. However, determination of the sites of virus multiplication indicated that exposure to ozone resulted in a less widespread infection of the lung parenchyma. Furthermore, ozone exposure reduced the antiviral immune response as shown by reduced numbers of phenotypically quantitated T- and B-lymphocytes recovered from lung tissues and reduction of serum antibody titers. Since the pathogenesis of influenza virus infection depends on both the site of viral replication and the antiviral immune response, these studies suggest that redistribution of virus growth in murine lungs and immunosuppressive mechanisms are factors in the ozone-reduced disease severity.

  5. Rat lung response to ozone and fine particulate matter (PM2.5) exposures.

    PubMed

    Wang, Guanghe; Zhao, Jinzhuo; Jiang, Rongfang; Song, Weimin

    2015-03-01

    Exposure to different ambient pollutants maybe more toxic to lung than exposure to a single pollutant. In this study, we discussed the inflammation and oxidative stress responses of rat lung caused by ozone and PM2.5 versus that of rats exposed to saline, ozone, or single PM2.5 . Wistar rats inhaled 0.8 ppm ozone or air for 4 h and then placed in air for 3 h following intratracheal instillation with 0, 0.2 (low dose), 0.8 (medium dose), 3.2 (high dose) mg/rat PM2.5 dissolved in sterile saline (0.25 mL/rat), repeated twice per week for 3 weeks, the cumulative doses of PM2.5 in animals were 1.2, 4.8, and 19.2 mg. Rats were sacrificed 24 h after the last (sixth) exposure. The collected bronchoalveolar lavage fluid (BALF) was analyzed for inflammatory cells and cytokines. Lung tissues were processed for light microscopic and transmission electron microscopic (TEM) examinations. Results showed that total cell number in BALF of PM2.5 -exposed groups were higher than control (p < 0.05). PM2.5 instillation caused dose-trend increase in tumor necrosis factor alpha (TNF-α), interleukin-6, lactate dehydrogenase, and total protein of BALF. Exposure to ozone alone only caused TNF-α significant change in above-mentioned indicators of lung injury. On the other hand, ozone could enhance PM2.5-induced inflammatory changes and pathological characters in rat lungs. SOD and GSH-Px activities in lung were reduced in PM2.5-exposed rats with and without prior ozone exposure compared to control. To determine whether the PM2.5 and ozone affect endothelium system, iNOS, eNOS, and ICAM-1 mRNA levels in lung were analyzed by real-time PCR. These data demonstrated that inflammation and oxidative stress were involved in toxicology mechanisms of PM2.5 in rat lung and ozone potentiated these effects induced by PM2.5. These results have implications for understanding the pulmonary effects induced by ozone and PM2.5.

  6. Modulation of bronchial epithelial cell barrier function by in vitro ozone exposure

    SciTech Connect

    Yu, Xiao-Ying; Takahashi, Nobuyoshi; Croxton, T.L.; Spannhake, E.W.

    1994-12-01

    The epithelial cells lining the small, peripheral airways function as important targets for the action of inspired ozone. Loss of epithelial barrier integrity in these regions is a common element in ozone-induced airway inflammation. To investigate the direct effect of ozone on epithelial barrier function, canine bronchial epithelial (CBE) cells grown with an air interface were exposed for 3hr to 0.2, 0.5, or 0.8 ppm ozone or to air. Mannitol flux, used as an index of paracellular permeability, increased above air controls by 461%, 774%, and 1172% at the three ozone concentrations, respectively. Transcellular electrical resistance exhibited a dose-related decrease. The immediate effect of 0.8 ppm ozone on permeability was significantly inhibited by preincubation for 48 hr in the presence of 1 ng/ml vitamin E (33%) or 1 {mu}M vitamin A (34%). Responses to 0.5 ppm or 0.8 ppm were inhibited by pretreatment of the cells with 0.1 {mu}M of the actin polymerizing agent phalloidin (34% and 25% inhibition, respectively). The increases in permeability induced by 0.2 and 0.5 ppm ozone were attenuated by 54% and 22%, respectively, at 18 hr after exposure, whereas that to 0.8 ppm was further enhanced by 42% at this time. The effects of ozone are modulated by the availability of antioxidants to the cells and appear to be associated with cytoskeletal dysfunction in CBE cells. The data are consistent with a loss of barrier function linked to a direct oxidative effect of ozone on individual CBE cells and indicate that the reversible or progressive nature of this effect is dose dependent. 31 refs., 5 figs.

  7. Prolonged exposure of cholestatic rats to complete dark inhibits biliary hyperplasia and liver fibrosis

    PubMed Central

    Han, Yuyan; Onori, Paolo; Meng, Fanyin; DeMorrow, Sharon; Venter, Julie; Francis, Heather; Franchitto, Antonio; Ray, Debolina; Kennedy, Lindsey; Greene, John; Renzi, Anastasia; Mancinelli, Romina; Gaudio, Eugenio; Glaser, Shannon

    2014-01-01

    Biliary hyperplasia and liver fibrosis are common features in cholestatic liver disease. Melatonin is synthesized by the pineal gland as well as the liver. Melatonin inhibits biliary hyperplasia of bile duct-ligated (BDL) rats. Since melatonin synthesis (by the enzyme serotonin N-acetyltransferase, AANAT) from the pineal gland increases after dark exposure, we hypothesized that biliary hyperplasia and liver fibrosis are diminished by continuous darkness via increased melatonin synthesis from the pineal gland. Normal or BDL rats (immediately after surgery) were housed with light-dark cycles or complete dark for 1 wk before evaluation of 1) the expression of AANAT in the pineal gland and melatonin levels in pineal gland tissue supernatants and serum; 2) biliary proliferation and intrahepatic bile duct mass, liver histology, and serum chemistry; 3) secretin-stimulated ductal secretion (functional index of biliary growth); 4) collagen deposition, liver fibrosis markers in liver sections, total liver, and cholangiocytes; and 5) expression of clock genes in cholangiocytes. In BDL rats exposed to dark there was 1) enhanced AANAT expression/melatonin secretion in pineal gland and melatonin serum levels; 2) improved liver morphology, serum chemistry and decreased biliary proliferation and secretin-stimulated choleresis; and 4) decreased fibrosis and expression of fibrosis markers in liver sections, total liver and cholangiocytes and reduced biliary expression of the clock genes PER1, BMAL1, CLOCK, and Cry1. Thus prolonged dark exposure may be a beneficial noninvasive therapeutic approach for the management of biliary disorders. PMID:25214401

  8. Growth response of two varieties of slash-pine seedlings to chronic ozone exposures

    SciTech Connect

    Hogsett, W.E.; Plocher, M.; Wildman, V.; Tingey, D.T.; Bennett, J.P.

    1985-01-01

    Two geographical varieties of Pinus elliottii (Engelm.) seedlings, elliottii and densa, were exposed continuously to two daily peak exposure profiles of ozone having 7-h seasonal means of 0.104 and 0.076 ppm and charcoal-filtered air over a 112-day period. The profiles represented a daily rise and decline of hourly ozone concentration. They were constructed with a daily hourly maximum, which for one profile (0.126 micro l/l) exceeded the current ozone standard daily; the standard was not exceeded for the other profile (0.094 micro l/l). Destructive harvests at 7-day intervals over the exposure period were employed to assess visible injury and to construct growth curves for stem diameter, plant height, top and root dry weight, and needle number and length.

  9. Structural and functional localization of airway effects from episodic exposure of infant monkeys to allergen and/or ozone

    SciTech Connect

    Joad, Jesse P. . E-mail: jesse.joad@ucdmc.ucdavis.edu; Kott, Kayleen S.; Bric, John M.; Peake, Janice L.; Plopper, Charles G.; Schelegle, Edward S.; Gershwin, Laurel J.; Pinkerton, Kent E.

    2006-08-01

    Both allergen and ozone exposure increase asthma symptoms and airway responsiveness in children. Little is known about how these inhalants may differentially modify airway responsiveness in large proximal as compared to small distal airways. We evaluated whether bronchi and respiratory bronchioles from infant monkeys exposed episodically to allergen and/or ozone differentially develop intrinsic hyperresponsiveness to methacholine and whether eosinophils and/or pulmonary neuroendocrine cells play a role. Infant monkeys were exposed episodically for 5 months to: (1) filtered air, (2) aerosolized house dust mite allergen, (3) ozone 0.5 ppm, or (4) house dust mite allergen + ozone. Studying the function/structure relationship of the same lung slices, we evaluated methacholine airway responsiveness and histology of bronchi and respiratory bronchioles. In bronchi, intrinsic responsiveness was increased by allergen exposure, an effect reduced by bombesin antagonist. In respiratory bronchioles, intrinsic airway responsiveness was increased by allergen + ozone exposure. Eosinophils were increased by allergen and allergen + ozone exposure in bronchi and by allergen exposure in respiratory bronchioles. In both airways, exposure to allergen + ozone resulted in fewer tissue eosinophils than did allergen exposure alone. In bronchi, but not in respiratory bronchioles, the number of eosinophils and neuroendocrine cells correlated with airway responsiveness. We conclude that episodically exposing infant monkeys to house dust mite allergen with or without ozone increased intrinsic airway responsiveness to methacholine in bronchi differently than in respiratory bronchioles. In bronchi, eosinophils and neuroendocrine cells may play a role in the development of airway hyperresponsiveness.

  10. Exposure to medium and high ambient levels of ozone causes adverse systemic inflammatory and cardiac autonomic effects.

    PubMed

    Arjomandi, Mehrdad; Wong, Hofer; Donde, Aneesh; Frelinger, Jessica; Dalton, Sarah; Ching, Wendy; Power, Karron; Balmes, John R

    2015-06-15

    Epidemiological evidence suggests that exposure to ozone increases cardiovascular morbidity. However, the specific biological mechanisms mediating ozone-associated cardiovascular effects are unknown. To determine whether short-term exposure to ambient levels of ozone causes changes in biomarkers of cardiovascular disease including heart rate variability (HRV), systemic inflammation, and coagulability, 26 subjects were exposed to 0, 100, and 200 ppb ozone in random order for 4 h with intermittent exercise. HRV was measured and blood samples were obtained immediately before (0 h), immediately after (4 h), and 20 h after (24 h) each exposure. Bronchoscopy with bronchoalveolar lavage (BAL) was performed 20 h after exposure. Regression modeling was used to examine dose-response trends between the endpoints and ozone exposure. Inhalation of ozone induced dose-dependent adverse changes in the frequency domains of HRV across exposures consistent with increased sympathetic tone [increase of (parameter estimate ± SE) 0.4 ± 0.2 and 0.3 ± 0.1 in low- to high-frequency domain HRV ratio per 100 ppb increase in ozone at 4 h and 24 h, respectively (P = 0.02 and P = 0.01)] and a dose-dependent increase in serum C-reactive protein (CRP) across exposures at 24 h [increase of 0.61 ± 0.24 mg/l in CRP per 100 ppb increase in ozone (P = 0.01)]. Changes in HRV and CRP did not correlate with ozone-induced local lung inflammatory responses (BAL granulocytes, IL-6, or IL-8), but changes in HRV and CRP were associated with each other after adjustment for age and ozone level. Inhalation of ozone causes adverse systemic inflammatory and cardiac autonomic effects that may contribute to the cardiovascular mortality associated with short-term exposure.

  11. Germ cell studies in mice after prolonged exposure to nitrous oxide

    SciTech Connect

    Mazze, R.I.; Rice, S.A.; Wyrobek, A.J.; Felton, J.S.; Brodsky, J.B.; Baden, J.M.

    1983-03-15

    Male and female Swiss Webster (SW) mice, age 13 to 14 weeks, were exposed by inhalation for 4 hr per day, 5 days per week, for 14 weeks, to either room air, 0.5% nitrous oxide, 5.0% nitrous oxide, or 50% nitrous oxide. Murine germ cells were examined for evidence of injury after this exposure. A group of male mice were treated with methyl methanesulfonate (MMS) as a positive control for sperm abnormalities while a group of female mice were treated with 3-methylcholanthrene (3-MC) as a positive control for oocyte destruction. There were no significant differences among the four inhalation exposure groups in testes weight, percentage of abnormally shaped sperm, sperm count, or histologic appearance of the testes; the mean percentage (+/- SE) of abnormal sperm ranged from 8.9 +/- 2.4 (5.0% nitrous oxide) to 13.5 +/- 0.5 (50% nitrous oxide) with a concurrent control value of 10.4 +/- 2.3%. In the positive control experiment, 25.2 +/- 4.1% of sperm from mice treated with MMS were abnormal compared with 2.5 +/- 0.3% of sperm from mice treated with saline (p less than 0.001), indicating that sperm of SW mice are sensitive to chemical damage. There was no significant difference between the mean number of oocytes in mice treated with 50% nitrous oxide (33.3 +/- 14.4) and in control mice (29.8 +/- 8.0). In the positive control experiment, mice treated with 3-MC had significantly fewer (p less than 0.001) primordial oocytes, 67.2 +/- 19.5 compared with control mice, 222.4 +/- 21.9, indicating that this strain is sensitive to chemical damage of the ovary. Thus, murine germ cells showed no evidence of toxic effects due to prolonged exposure to nitrous oxide.

  12. TOPICAL REVIEW: Climate change, ozone depletion and the impact on ultraviolet exposure of human skin

    NASA Astrophysics Data System (ADS)

    Diffey, Brian

    2004-01-01

    For 30 years there has been concern that anthropogenic damage to the Earth's stratospheric ozone layer will lead to an increase of solar ultraviolet (UV) radiation reaching the Earth's surface, with a consequent adverse impact on human health, especially to the skin. More recently, there has been an increased awareness of the interactions between ozone depletion and climate change (global warming), which could also impact on human exposure to terrestrial UV. The most serious effect of changing UV exposure of human skin is the potential rise in incidence of skin cancers. Risk estimates of this disease associated with ozone depletion suggest that an additional peak incidence of 5000 cases of skin cancer per year in the UK would occur around the mid-part of this century. Climate change, which is predicted to lead to an increased frequency of extreme temperature events and high summer temperatures, will become more frequent in the UK. This could impact on human UV exposure by encouraging people to spend more time in the sun. Whilst future social trends remain uncertain, it is likely that over this century behaviour associated with climate change, rather than ozone depletion, will be the largest determinant of sun exposure, and consequent impact on skin cancer, of the UK population.

  13. Exposure to ozone modulates human airway protease/antiprotease balance contributing to increased influenza A infection

    EPA Science Inventory

    Exposure to oxidant air pollution is associated with Increased respiratory morbiditses and susceptibility to Infections Ozone is a commonly encountered oxidant air pollutant, yet Its effects on influenza infections in humans are not known ‘the greater Mexico City area was the pri...

  14. Human Ozone (O3) Exposure Alters Serum Profile of Lipid Metabolites

    EPA Science Inventory

    HUMAN OZONE (O3) EXPOSURE ALTERS SERUM PROFILE OF LIPID METABOLITES Miller, D B.1; Kodavanti, U P.2 Karoly, E D.3; Cascio W.E2, Ghio, A J. 21. UNC-Chapel Hill, Chapel Hill, N.C., United States. 2. NHEERL, U.S. EPA, RTP, N.C., United States. 3. METABOLON INC., Durham, N.C., United...

  15. Climate change, ozone depletion and the impact on ultraviolet exposure of human skin.

    PubMed

    Diffey, Brian

    2004-01-01

    For 30 years there has been concern that anthropogenic damage to the Earth's stratospheric ozone layer will lead to an increase of solar ultraviolet (UV) radiation reaching the Earth's surface, with a consequent adverse impact on human health, especially to the skin. More recently, there has been an increased awareness of the interactions between ozone depletion and climate change (global warming), which could also impact on human exposure to terrestrial UV. The most serious effect of changing UV exposure of human skin is the potential rise in incidence of skin cancers. Risk estimates of this disease associated with ozone depletion suggest that an additional peak incidence of 5000 cases of skin cancer per year in the UK would occur around the mid-part of this century. Climate change, which is predicted to lead to an increased frequency of extreme temperature events and high summer temperatures, will become more frequent in the UK. This could impact on human UV exposure by encouraging people to spend more time in the sun. Whilst future social trends remain uncertain, it is likely that over this century behaviour associated with climate change, rather than ozone depletion, will be the largest determinant of sun exposure, and consequent impact on skin cancer, of the UK population.

  16. Effects of combinations of diesel exhaust and ozone exposure on lung function in human volunteers.

    EPA Science Inventory

    Ozone (03) exposure induces changes in human lung function, typically seen as a decrease in forced expiratory volume in one sec (FEV1) and forced vital capacity (FVC). Because people are usually exposed to other ambient air pollutants simultaneously with 03, there may be interact...

  17. Effects Of Combinations of Ozone and Diesel Exhaust Exposures On Blood, Cardiac, And Lung Endpoints

    EPA Science Inventory

    Human subjects were exposed to combinations of 300 ppb ozone (03) and 300 ug/m3 diesel exhaust (DE) to examine if synergistic effects were observed. Subjects received either filtered air (FA), 03, DE, or DE+03 on Day 1, followed by only 03 exposures on Day 2, and a follow-up on D...

  18. The Effect of Lake Temperatures and Emissions on Ozone Exposure in the Western Great Lakes Region

    SciTech Connect

    Fast, Jerome D. ); Heilman, Warren E.

    2003-09-01

    A meteorological-chemical model with a 12-km horizontal grid spacing was used to simulate the evolution of ozone over the western Great Lakes region during a 30-day period in the summer of 1999. High ozone production rates were produced over the surface of the lakes as a result of stable atmospheric conditions that trapped ozone precursors within a shallow layer during the day. Simulations with lake temperatures derived from either satellite measurements or climatological values produced ozone mixing ratios over the lakes and around the lake shores that differed by as much as 50 ppb while differences over land were usually 10 ppb or less. Through another series of sensitivity studies that varied ozone precursor emissions, it was shown that a reduction of 50% NOx or VOC would lower the 60 ppb ozone exposure by up to 50 h per month in the remote forest regions over the northern Great Lakes. The implications of these results on future climate change and air quality in the region is discussed.

  19. Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

    NASA Astrophysics Data System (ADS)

    Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian

    2016-03-01

    Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

  20. Ozone exposure and flux-based response functions for photosynthetic traits in wheat, maize and poplar.

    PubMed

    Bagard, Matthieu; Jolivet, Yves; Hasenfratz-Sauder, Marie-Paule; Gérard, Joëlle; Dizengremel, Pierre; Le Thiec, Didier

    2015-11-01

    Ozone exposure- and dose-response relationships based on photosynthetic leaf traits (CO2 assimilation, chlorophyll content, Rubisco and PEPc activities) were established for wheat, maize and poplar plants grown in identical controlled conditions, providing a comparison between crop and tree species, as well as between C3 and C4 plants. Intra-specific variability was addressed by comparing two wheat cultivars with contrasting ozone tolerance. Depending on plant models and ozone levels, first-order, second-order and segmented linear regression models were used to derive ozone response functions. Overall, flux-based functions appeared superior to exposure-based functions in describing the data, but the improvement remained modest. The best fit was obtained using the POD0.5 for maize and POD3 for poplar. The POD6 appeared relevant for wheat, although intervarietal differences were found. Our results suggest that taking into account the dynamics of leaf antioxidant capacity could improve current methods for ozone risk assessment for plants.

  1. Effects of in vitro ozone exposure on peroxidative damage, membrane leakage, and taurine content of rat alveolar macrophages

    SciTech Connect

    Banks, M.A.; Porter, D.W.; Martin, W.G.; Castranova, V. )

    1990-08-01

    Rat alveolar macrophages (AM) were isolated by pulmonary lavage, allowed to adhere to a tissue culture flask, and then exposed to 0.45 +/- 0.05 ppm ozone. After exposures ranging from 0 to 60 min, the medium was decanted and cells were harvested. Cells were assayed for oxidant damage and media analyzed for leakage of intracellular components. Increasing length of exposure to ozone resulted in a decreased number of adherent AM and decreased cell viability. Resting and zymosan-stimulated chemiluminescence increased immediately after ozone exposure and reached a maximum at 15-30 min, then declined to initial levels after 60 min of ozone exposure. Lipid peroxidation and leakage of protein and K+ ions increased with increasing length of exposure to ozone, while leakage of reduced and oxidized glutathione increased through 30 min, then declined (reduced) or leveled off (oxidized). Activity of the Na+/K+ ATPase decreased with time while intracellular taurine concentration exhibited an initial rise, peaked at 30 min, and then returned to the untreated level. Leakage of taurine into the medium increased with time of exposure, suggesting that exposure of AM to ozone results in a shift from bound to free intracellular taurine. These data indicate that in vitro exposure of AM to ozone results in a time-dependent alteration of cell function, membrane integrity, and viability.

  2. Effect of exposures to ambient ozone on ventilatory lung function in children

    SciTech Connect

    Higgins, I.T.; D'Arcy, J.B.; Gibbons, D.I.; Avol, E.L.; Gross, K.B. )

    1990-05-01

    This study was undertaken to determine if the ventilatory capacity of children is affected by hourly concentrations of ozone inhaled during their daily activity. Over a 3-wk period children who were attending a summer camp in the San Bernardino mountains of California performed spirometry up to three times per day during their stay at the camp. Ozone, oxides of nitrogen, sulfur dioxide, temperature, and relative humidity were measured continuously. Daily average measurements of total suspended particulate and the PM10 particulate fraction were also made. Hourly ozone concentrations at the time of testing varied between 20 and 245 ppb. Regressions of each individual's FEV1 and FVC supported the view that high ozone levels reduced these lung function parameters. The average regression coefficient for FEV1 on ozone was -0.39 ml/ppb (SEM = 0.12) and for FVC -0.44 ml/ppb (SEM = 0.15), both of which were significantly different from zero. Statistical allowance for temperature and humidity increased the magnitude of these slopes. Nitrogen dioxide never exceeded 40 ppb during the time of testing and averaged 13 ppb. Sulfur dioxide's highest measurement was 8 ppb and often was at the limit of detection. Neither NO2 nor SO2 was considered in the statistical modeling. Data were divided based on whether each subject had been exposed to levels of ozone in excess of the National Ambient Air Quality Standard (NAAQS) during the several hours previous to being tested. Exposures exceeding the NAAQS indicated a significant negative relationship between ozone and FEV1, FVC, and PEFR. Data for nonexceedance periods did not indicate this negative relationship for any of the three lung function parameters, but it could not be determined if this was due to an absence of an ozone effect or to a combination of the increased variability and decreased size of this data subset.

  3. Overview of ozone human exposure and health risk analyses used in the U.S. EPA's review of the ozone air quality standard.

    SciTech Connect

    Whitfield, R. G.

    1999-03-04

    This paper presents an overview of the ozone human exposure and health risk analyses developed under sponsorship of the U.S. Environmental Protection Agency (EPA). These analyses are being used in the current review of the national ambient air quality standards (NAAQS) for ozone. The analyses consist of three principal steps: (1) estimating short-term ozone exposure for particular populations (exposure model); (2) estimating population response to exposures or concentrations (exposure-response or concentration-response models); and (3) integrating concentrations or exposure with concentration-response or exposure-response models to produce overall risk estimates (risk model). The exposure model, called the probabilistic NAAQS exposure model for ozone (pNEM/03), incorporates the following factors: hourly ambient ozone concentrations; spatial distribution of concentrations; ventilation state of individuals at time of exposure; and movement of people through various microenvironments (e.g., outdoors, indoors, inside a vehicle) of varying air quality. Exposure estimates are represented by probability distributions. Exposure-response relationships have been developed for several respiratory symptom and lung function health effects, based on the results of controlled human exposure studies. These relationships also are probabilistic and reflect uncertainties associated with sample size and variability of response among subjects. The analyses also provide estimates of excess hospital admissions in the New York City area based on results from an epidemiology study. Overall risk results for selected health endpoints and recently analyzed air quality scenarios associated with alternative 8-hour NAAQS and the current 1-hour standard for outdoor children are used to illustrate application of the methodology.

  4. Randomized Trial of Prolonged Exposure for Posttraumatic Stress Disorder with and without Cognitive Restructuring: Outcome at Academic and Community Clinics

    ERIC Educational Resources Information Center

    Foa, Edna B.; Hembree, Elizabeth A.; Cahill, Shawn P.; Rauch, Sheila A. M.; Riggs, David S.; Feeny, Norah C.; Yadin, Elna

    2005-01-01

    Female assault survivors (N = 171) with chronic posttraumatic stress disorder (PTSD) were randomly assigned to prolonged exposure (PE) alone, PE plus cognitive restructuring (PE/CR), or wait-list (WL). Treatment, which consisted of 9-12 sessions, was conducted at an academic treatment center or at a community clinic for rape survivors. Evaluations…

  5. Integrating Dialectical Behavior Therapy and Prolonged Exposure to Treat Co-Occurring Borderline Personality Disorder and PTSD: Two Case Studies

    ERIC Educational Resources Information Center

    Harned, Melanie S.; Linehan, Marsha M.

    2008-01-01

    Despite the high rate of trauma and PTSD among individuals with borderline personality disorder (BPD), no studies have specifically evaluated the treatment of PTSD in a BPD population. These case studies illustrate the use of a protocol based on prolonged exposure therapy that can be integrated into standard dialectical behavior therapy to treat…

  6. Exposure to 1 ppm ozone attenuates the immediate antigenic response of canine peripheral airways

    SciTech Connect

    Kleeberger, S.R.; Kolbe, J.; Turner, C.; Spannhake, E.W. )

    1989-01-01

    The effect of oxidant exposure on the immediate airway response to immunologic challenge is controversial. We investigated the response of canine peripheral airways to antigen aerosol, 1-3 h and 24 h after a 5-min exposure to 1 ppm ozone. In dogs that were natively sensitive to Ascaris suum antigen, resistance to flow through the collateral system (Rcs) was measured using the wedged bronchoscope technique. In eight dogs, four sublobar segments of each lung were wedged: two were exposed to ozone for 5 min and two (control) received air with 5% CO2. Ozone caused a mean ( +/- SE) increase in Rcs of 75 +/- 15%, which returned to baseline after 1-3 h. The increase in Rcs elicited by subsequent administration of antigen aerosol (25 microliters, 0.27 mg protein/ml) to the ozone-exposed segments (312.0 +/- 70.6%) was attenuated by 22% compared to controls (398.9 +/- 83.0%; p less than .05). In another series of experiments (n = 5), segments were exposed to ozone or air and challenged with antigen 24 h later and a significant attenuation (38%) of the antigen-induced increase in Rcs was detected compared to controls (178.5 +/- 57.9 vs 289.0 +/- 62.2; p less than .05). Cellular influx of polymorphonuclear leukocytes (PMNs) was not detected by bronchoalveolar lavage (BAL) 1-3 h after ozone, but was found after 24 h (19.8 vs. 4.7%; p less than .01). A significant increase in PMNs was detected in exposed subepithelial tissues 1-3 h after ozone compared to unexposed tissues. Tissue PMNs were not significantly different from unexposed tissues after 24 h, but a shift toward degranulation of mast cells was detected in ozone-exposed tissues at this time. These data suggest that the Rcs response to antigen is attenuated 1-3 h and 24 h after acute (5 min) exposure to 1 ppm ozone, and this effect occurs independently of PMNs in the airways.

  7. Absence of acute ocular damage in humans after prolonged exposure to intense RF EMF.

    PubMed

    Adibzadeh, F; van Rhoon, G C; Verduijn, G M; Naus-Postema, N C; Paulides, M M

    2016-01-21

    The eye is considered to be a critical organ when determining safety standards for radio frequency (RF) radiation. Experimental data obtained using animals showed that RF heating of the eye, particularly over a specific threshold, can induce cataracts. During the treatment of cancer in the head and neck by hyperthermia, the eyes receive a considerable dose of RF radiation due to stray radiation from the prolonged (60 min) and intense exposure at 434 MHz of this region. In the current study, we verified the exposure guidelines for humans by determining the association between the electromagnetic and thermal dose in the eyes with the reported ocular effects. We performed a simulation study to retrospectively assess the specific absorption rate (SAR) and temperature increase in the eyes of 16 selected patients (encompassing a total of 74 treatment sessions) whose treatment involved high power delivery as well as a minimal distance between the tumor site and the eye. Our results show that the basic restrictions on the peak 10 g spatial-averaged SAR (10 W kg(-1)) and peak tissue temperature increase (1 °C) are exceeded by up to 10.4 and 4.6 times, on average, and by at least 6.2 and 1.8 times when considering the lower limit of the 95% confidence interval. Evaluation of the acute effects according to patients' feedback (all patients), the common toxicity criteria scores (all patients) and an ophthalmology investigation (one patient with the highest exposure) revealed no indication of any serious acute ocular effect, even though the eyes were exposed to high electromagnetic fields, leading to a high thermal dose. We also found that, although there is a strong correlation (R (2) =  0.88) between the predicted induced SAR and temperature in the eye, there are large uncertainties regarding the temperature-SAR relationship. Given this large uncertainty (129%) compared with the uncertainty of 3D temperature simulations (61%), we recommend using temperature simulations as a

  8. Absence of acute ocular damage in humans after prolonged exposure to intense RF EMF

    NASA Astrophysics Data System (ADS)

    Adibzadeh, F.; van Rhoon, G. C.; Verduijn, G. M.; Naus-Postema, N. C.; Paulides, M. M.

    2016-01-01

    The eye is considered to be a critical organ when determining safety standards for radio frequency (RF) radiation. Experimental data obtained using animals showed that RF heating of the eye, particularly over a specific threshold, can induce cataracts. During the treatment of cancer in the head and neck by hyperthermia, the eyes receive a considerable dose of RF radiation due to stray radiation from the prolonged (60 min) and intense exposure at 434 MHz of this region. In the current study, we verified the exposure guidelines for humans by determining the association between the electromagnetic and thermal dose in the eyes with the reported ocular effects. We performed a simulation study to retrospectively assess the specific absorption rate (SAR) and temperature increase in the eyes of 16 selected patients (encompassing a total of 74 treatment sessions) whose treatment involved high power delivery as well as a minimal distance between the tumor site and the eye. Our results show that the basic restrictions on the peak 10 g spatial-averaged SAR (10 W kg-1) and peak tissue temperature increase (1 °C) are exceeded by up to 10.4 and 4.6 times, on average, and by at least 6.2 and 1.8 times when considering the lower limit of the 95% confidence interval. Evaluation of the acute effects according to patients’ feedback (all patients), the common toxicity criteria scores (all patients) and an ophthalmology investigation (one patient with the highest exposure) revealed no indication of any serious acute ocular effect, even though the eyes were exposed to high electromagnetic fields, leading to a high thermal dose. We also found that, although there is a strong correlation (R 2  =  0.88) between the predicted induced SAR and temperature in the eye, there are large uncertainties regarding the temperature-SAR relationship. Given this large uncertainty (129%) compared with the uncertainty of 3D temperature simulations (61%), we recommend using temperature

  9. Plasmodium berghei infection in mice: effect of low-level ozone exposures

    SciTech Connect

    Moore, G.S.; Calabrese, E.J.; Molteni, K.H.

    1984-07-01

    Animal and human studies have accumulated that report erythrocyte effects from inhaled ozone (O/sub 3/). It was the purpose of this research to demonstrate the effects of O/sub 3/ exposure on the course of parasitemia in mice. A study was designed utilizing Plasmodium berghei, a murine malarial parasite host-specific for rodents, as the specific pathogen. The purpose of this project was to study mortality and percent parasitemia in the A/J mouse first infected with P. berghei and then exposed to low levels of ozone.

  10. Prognostic evaluation of spinal microlesions under exposure of longitudinal blow accelerations of prolonged action.

    PubMed

    Mazurin YuV; Stupakov, G P

    1995-01-01

    The performed experimental investigations were aimed at qualitative and approximate quantitative estimation of parameters of cumulated microtraumatic destructions in spine, leading to its lowered bearing capabilities under prolonged loading with compressing exposures corresponding to high levelled maneuverable accelerations, which exceed 5 G and onset rates 10 G/s and more. Process of microlesions in bone tissues of vertebral bodies at this range of accelerations is not still sufficiently studied. Practical importance of these effects has close relation as to problem of high intensity flight maneuvering accelerations with onset rates up to 10 G/s and higher as well as to estimation if impact acceleration tolerance in ejection event with controllable flightpath of kicked out capatult seat. The data, received in natural experiments on spinal segments T11-L3 with fixation of acoustical emission signals (AES), suggest that stage of minor lesion of vertebral bodies (the first degree of severity), characterizing by avalanche-like increment of acoustical emission signals and starting point of specific crack in loading flow chart, may be pertained as having fragile character. PMID:11538944

  11. Static and dynamic vestibulo-cervico-ocular responses after prolonged exposure to microgravity.

    PubMed

    Kornilova, L N; Sagalovitch, S V; Temnikova, V V; Yakushev, A G

    2007-01-01

    The vestibular function was investigated in 13 Russian crew members of the ISS missions on days 1(2), 4(5), and 8(9) after prolonged exposure to microgravity (126 to 195 days). The static torsional otolith-cervico-ocular reflex was studied, as well as the dynamic vestibulo-cervico-ocular responses, vestibular reactivity, and spontaneous oculomotor activity using videooculography (VOG) and electrooculography (EOG) for simultaneous recording of eye movements. On days 1-2 of return to the gravity (R+1-2), the cosmonauts were found to increase the spontaneous oculomotor activity (floating eye movements, both typical and atypical forms of spontaneous nystagmus, square wave jerks, gaze nystagmus) with the head held in the vertical position. The otolith function during static head inclinations to the right or left shoulder at 30 degrees was suppressed as determined by the inversion or absence, or reduction by half of the amplitude of torsional compensatory eye counter-rolling and the vestibular reactivity during head yaw movements at 0.125 Hz was increased as revealed by a lowered threshold and an increased intensity of vestibular nystagmus. The pattern, depth, dynamics, and velocity of the vestibular function recovery varied with individual participants in the investigation. However, the suppressed otolith functioning in the period of readaptation to the normal gravity was, as a rule, accompanied by an exaggerated vestibular reactivity. PMID:18626133

  12. Incorporation of glucose carbons into rat lung lipids after exposure to 0.6 ppm ozone.

    PubMed

    Bassett, D J; Rabinowitz, J L

    1985-05-01

    Continuous exposure to low concentrations of ozone has previously been associated with proliferation of lung alveolar type II epithelial cells. In this study, 14C incorporation into tissue lipids was determined in isolated rat lungs by perfusion with [U-14C]glucose, at a time of maximal hyperplasia brought about by 3 days continuous exposure to 0.6 ppm ozone. Ozone exposed lungs exhibited increased rates of glycolytic energy production, indicated by an 89% increase in 3H2O generation on perfusion with [5-3H]glucose, from a control value of 17.5 +/- 2.1 mumol X h-1 X g-1 X dry wt-1 (+/- SE, n = 4). Ozone exposure resulted in enhanced 14C incorporations into glyceride-glycerol and fatty acid moieties of lung lipids of 95 and 180%, respectively, with a greater proportion of label being recovered in shorter chain fatty acids. Although increased labeling was observed in both neutral and phospholipids, the pattern of 14C recovery suggested a relative increased glucose carbon incorporation into lung free fatty acids, phosphatidic acid, and such membrane associated lipids as phosphatidylinositol and those containing sphingosine. These results are consistent with the needs of a dividing cell population for enhanced energy production and synthesis of new lipids.

  13. A probabilistic assessment of health risks associated with short-term exposure to tropospheric ozone

    SciTech Connect

    Whitfield, R.G; Biller, W.F.; Jusko, M.J.; Keisler, J.M.

    1996-06-01

    The work described in this report is part of a larger risk assessment sponsored by the U.S. Environmental Protection Agency. Earlier efforts developed exposure-response relationships for acute health effects among populations engaged in heavy exertion. Those efforts also developed a probabilistic national ambient air quality standards exposure model and a general methodology for integrating probabilistic exposure-response relation- ships and exposure estimates to calculate overall risk results. Recently published data make it possible to model additional health endpoints (for exposure at moderate exertion), including hospital admissions. New air quality and exposure estimates for alternative national ambient air quality standards for ozone are combined with exposure-response models to produce the risk results for hospital admissions and acute health effects. Sample results explain the methodology and introduce risk output formats.

  14. Early life exposure to allergen and ozone results in altered development in adolescent rhesus macaque lungs

    SciTech Connect

    Herring, M.J.; Putney, L.F.; St George, J.A.; Avdalovic, M.V.; Schelegle, E.S.; Miller, L.A.; Hyde, D.M.

    2015-02-15

    In rhesus macaques, previous studies have shown that episodic exposure to allergen alone or combined with ozone inhalation during the first 6 months of life results in a condition with many of the hallmarks of asthma. This exposure regimen results in altered development of the distal airways and parenchyma (Avdalovic et al., 2012). We hypothesized that the observed alterations in the lung parenchyma would be permanent following a long-term recovery in filtered air (FA) housing. Forty-eight infant rhesus macaques (30 days old) sensitized to house dust mite (HDM) were treated with two week cycles of FA, house dust mite allergen (HDMA), ozone (O{sub 3}) or HDMA/ozone (HDMA + O{sub 3}) for five months. At the end of the five months, six animals from each group were necropsied. The other six animals in each group were allowed to recover in FA for 30 more months at which time they were necropsied. Design-based stereology was used to estimate volumes of lung components, number of alveoli, size of alveoli, distribution of alveolar volumes, interalveolar capillary density. After 30 months of recovery, monkeys exposed to HDMA, in either group, had significantly more alveoli than filtered air. These alveoli also had higher capillary densities as compared with FA controls. These results indicate that early life exposure to HDMA alone or HDMA + O{sub 3} alters the development process in the lung alveoli. - Highlights: • Abnormal lung development after postnatal exposure to ozone and allergen • This remodeling is shown as smaller, more numerous alveoli and narrower airways. • Allergen appears to have more of an effect than ozone during recovery. • These animals also have continued airway hyperresponsiveness (Moore et al. 2014)

  15. Protein cross-linking and oligomerization through dityrosine formation upon exposure to ozone

    NASA Astrophysics Data System (ADS)

    Liu, Fobang; Kampf, Christopher; Reinmuth-Selzle, Kathrin; Berkemeier, Thomas; Shiraiwa, Manabu; Pöschl, Ulrich

    2015-04-01

    Air pollution is a potential factor for the increasing prevalence of allergic diseases. Airborne allergenic proteins can be directly exposed to air pollution promoting post-translational modifications, which can enhance the allergenic potential of proteins. The formation of dimers or oligomers of allergenic proteins has been reported to result in an enhanced allergenicity. However, the oligomerization process for proteins at atmospherically relevant concentration of O3 is still largely unknown. In this study, the kinetics and reaction mechanism of protein oligomerization upon ozone exposure were studied at atmospherically relevant ozone concentrations and relative humidity (RH) in coated-wall flow tube experiments. Bovine Serum Albumin (BSA) was used as a model protein. Protein ozone exposure was studied for different protein phase-states, i.e. amorphous solid (45% RH experiments), semi-solid (96% RH experiments) and liquid (bulk solution experiments) to account for the differences of phase in atmospheric particulates, e.g., aerosol particles and cloud droplets. Product analysis was performed using a size exclusion chromatography-high performance liquid chromatography-diode array detector (SEC-HPLC-DAD). We demonstrate that protein cross-linking upon ozone exposure can be attributed to the formation of covalent intermolecular dityrosine species by gel electrophoretic and fluorescence spectroscopic methods. The exposure experiments indicate that in addition to ozone concentration, the oligomerization process was depending on the phase-state of protein. In liquid-phase experiments, dimer formation was significantly enhanced, thus indicating a potential relevance of in-cloud processes for protein oligomerization. The reactive turnover is higher at 96% RH compared to 45% RH, indicating a higher bulk diffusion coefficient at high RH, which is explicitly resolved by kinetic modeling. Further, the reactive turnover showed a strong correlation to particle surface

  16. Prolonged environmental exposure of arsenic through drinking water on the risk of hypertension and type 2 diabetes.

    PubMed

    Li, Xin; Li, Bing; Xi, Shuhua; Zheng, Quanmei; Lv, Xiuqiang; Sun, Guifan

    2013-11-01

    Prolonged exposure to inorganic arsenic has been a severe environmental public health issue worldwide in the recent decades. Increasing evidence has suggested a possible role of prolonged arsenic exposure through drinking water in the development of arsenic-induced chronic noncancer diseases, among which hypertension and type 2 diabetes (T2D) are the focus of concern. Although exposure to high levels of arsenic has been reported to be associated with excess risk of hypertension or T2D in a dose-dependent manner, the association has yet to be established, especially low-level exposure. This cross-sectional study was designed to evaluate the potential association between prolonged environmental arsenic exposure through drinking water and the prevalence of hypertension and T2D in Inner Mongolia, China, with emphasis on the assessment of low-level exposure. In this study (a total of 669 men and women), we found that the blood pressure levels were significantly correlated with cumulative arsenic exposure and that the systolic blood pressure of the subjects with arsenic exposure>50 μg/L was significantly higher than those of the subjects with <10 and 10-50 μg/L exposure. Significant prevalence of hypertension was found in the subjects of the >50 μg/L group both before and after adjustment for confounders. In addition, a significant negative relationship was found between urinary arsenic percentage of dimethylated arsenic (DMA%) and the prevalence of hypertension in the >50 μg/L group. However, low-level arsenic exposure (10-50 μg/L) was not statistically associated with hypertension. No significant difference of blood glucose was found among the groups with different arsenic exposure levels. No statistical association was found between arsenic exposure and T2D. Our findings suggested that prolonged arsenic exposure might play a role in the development of hypertension; however, only high-level arsenic was associated with the risk of hypertension. Our findings also

  17. Ozone changes under solar geoengineering: implications for UV exposure and air quality

    NASA Astrophysics Data System (ADS)

    Nowack, P. J.; Abraham, N. L.; Braesicke, P.; Pyle, J. A.

    2015-11-01

    Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term Solar Radiation Management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks such as ozone changes under this scenario. Including the composition changes, we find large reductions in surface UV-B irradiance, with implications for vitamin D production, and increases in surface ozone concentrations, both of which could be important for human health. We highlight that both tropospheric and stratospheric ozone changes should be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

  18. Exposure of surfactant protein A to ozone in vitro and in vivo impairs its interactions with alveolar cells

    SciTech Connect

    Oosting, R.S.; Van Iwaarden, J.F.; Van Bree, L.; Verhoef, J.; Van Golde, L.M.; Haagsman, H.P. )

    1992-01-01

    This study focused on the question of whether exposure of surfactant protein A (SP-A) to ozone affected properties of this protein that may be involved in regulating alveolar type II cell and alveolar macrophage functions. In vitro exposure of human or canine SP-A to ozone reduced the ability of this protein to inhibit phorbol-ester induced secretion of (3H)phosphatidylcholine by alveolar type II cells in culture. Ozone-exposed human SP-A showed a decreased ability to enhance phagocytosis of herpes simplex virus and to stimulate superoxide anion production by alveolar macrophages. Experiments with elastase showed that ozone-exposed canine SP-A was more susceptible to proteolysis. A conformational change of the protein could underlie this phenomenon. Surfactant isolated from ozone-exposed rats (0.4 ppm ozone for 12 h) was also less able to stimulate superoxide anion production by alveolar macrophages than surfactant from control rats, which suggested that SP-A in vivo was also susceptible to ozone. The results of this study suggest that SP-A-alveolar cell interactions can be inhibited by ozone exposure, which may contribute to the toxicity of ozone in the lungs.

  19. Impact of asthma, exposure period, and filters on human responses during exposures to ozone and its initiated chemistry products.

    PubMed

    Fadeyi, M O; Tham, K W; Wu, W Y

    2015-10-01

    The impact of asthma, exposure period, and filter condition downstream of the mixing box of air-conditioning system on building occupants' perceptual response, work performance, and salivary α-amylase secretion during exposures to ozone and its initiated chemistry products is studied. The experiments were conducted in a field environmental chamber (FEC) (240 m(3)) simulating an office environment. Experiments were conducted during periods when the air-handling system operated with new or used pleated panel filters at constant recirculation (7/h) and ventilation (1/h) rates. Average ozone and secondary organic aerosols (ozone-initiated chemistry products) measured during non-asthmatic and asthmatic subjects' 3-h exposures in the FEC were in the ranges approximately 20-37 ppb and approximately 1.6-3 μg/m(3), respectively. Asthmatic subjects' perceived odor intensity and sensory (eye, nose, and throat) irritation ratings were generally lower than those of non-asthmatic subjects, possibly explaining why asthmatic subjects accept perceived air quality more than non-asthmatic subjects. However, asthmatic subjects' perceived physiological-like symptom ratings (flu, chest tightness, and headache) and concentrations of secreted salivary α-amylase were generally higher than those of non-asthmatic subjects. Asthmatic subjects had significantly lower accuracy than non-asthmatic subjects in a task that required higher concentration although they had higher work speed. Filter condition did not make any significant difference for subjects' responses.

  20. Interaction of ozone exposure with airway hyperresponsiveness and inflammation induced by trimellitic anhydride in sensitized guinea pigs

    SciTech Connect

    Sun, Jian; Chung, K.Fan

    1997-09-01

    The effect of prior ozone (O{sub 3}) exposure on airway hyperresponsiveness and inflammation induced by trimellitic anhydride (TMA) has been investigated in TMA-sensitized guinea pigs. Airway responsiveness was measured as the concentration of acetylcholine needed to increase baseline lung resistance (RL) by 300% (PC300). Ozone (3 ppm, for 3 h) caused an increase in-log PC300 at 1 h after exposure, with return of -log PC300 to control levels at 8 h. Ozone also increased baseline RL at 8 h. TMA challenge increase -log PC300 in TMA-sensitized guinea pigs at 8 h after challenge from 3.85 {+-} 0.09 to 4.11 {+-} 0.09. Ozone exposure prior to TMA challenge prevented the induction of airway hyperresponsiveness with a mean -log PC300 of 3.51 {+-} 0.20, which was not different from that of control TMA-Sensitized group. Baseline RL was significantly higher in ozone-pretreated animals after TMA challenge when compared to those of either control or challenged with TMA alone. Ozone had no effect on TMA challenge-induced BAL eosinophilia and neutrophilia. We conclude that a single exposure to ozone inhibits the increase in airway responsiveness, but increases the bronchoconstrictor response induced by TMA in TMA-Sensitized guinea pigs; however, the inflammatory airway response to TMA is unchanged by preexposure to ozone. 29 refs., 2 figs., 1 tab.

  1. Clinical and pathological manifestations of cardiovascular disease in rat models: the influence of acute ozone exposure.

    PubMed

    Ramot, Yuval; Kodavanti, Urmila P; Kissling, Grace E; Ledbetter, Allen D; Nyska, Abraham

    2015-01-01

    Rodent models of cardiovascular diseases (CVD) and metabolic disorders are used for examining susceptibility variations to environmental exposures. However, cross-model organ pathologies and clinical manifestations are often not compared. We hypothesized that genetic CVD rat models will exhibit baseline pathologies and will thus express varied lung response to acute ozone exposure. Male 12-14-week-old healthy Wistar Kyoto (WKY), Wistar (WIS), and Sprague-Dawley (SD) rats and CVD-compromised spontaneously hypertensive (SH), fawn-hooded hypertensive (FHH), stroke-prone SH (SHSP), obese SH heart-failure (SHHF), obese diabetic JCR (JCR) rats were exposed to 0.0, 0.25, 0.5, or 1.0 ppm ozone for 4 h and clinical biomarkers, and lung, heart and kidney pathologies were compared immediately following (0-h) or 20-h later. Strain differences were observed between air-exposed CVD-prone and WKY rats in clinical biomarkers and in kidney and heart pathology. Serum cholesterol was higher in air-exposed obese SHHF and JCR compared to other air-exposed strains. Ozone did not produce lesions in the heart or kidney. CVD-prone and SD rats demonstrated glomerulopathy and kidney inflammation (WKY = WIS = SH < SD = SHSP < SHHF < JCR = FHH) regardless of ozone. Cardiac myofiber degeneration was evident in SH, SHHF, and JCR, while only JCR tends to have inflammation in coronaries. Lung pathology in air-exposed rats was minimal in all strains except JCR. Ozone induced variable alveolar histiocytosis and bronchiolar inflammation; JCR and SHHF were less affected. This study provides a comparative account of the clinical manifestations of disease and early-life organ pathologies in several rat models of CVD and their differential susceptibility to lung injury from air pollutant exposure.

  2. Pulmonary response to exposure to ozone of emphysematous rats

    SciTech Connect

    Yokoyama, E.; Nambu, Z.; Ichikawa, I.; Uchiyama, I.; Arakawa, H.

    1987-02-01

    Rats were treated with a single intratracheal instillation of 6.5 units elastase or normal saline. Seven weeks after treatment, the animals were exposed for 24 hr to filtered air or 1 ppm O3, and their lung functions were measured. The exposure to O3 resulted in functional changes depending mainly on peripheral airway obstruction, and the direction and degree of those functional changes were in general similar between the saline- and elastase-treated animals. Another group of saline- or elastase-treated rats were exposed to 3 ppm O3 for 3 hr and the edematous response of their lungs was again similar. These results indicate that elastase-treated lungs responded to the exposure to O3 in a fashion similar to normal lungs in rats, but lung damage caused by the exposure to O3 superimposed over preexisting emphysematous damage, resulted in an additional lessening of the margin of pulmonary reserve capacity.

  3. Growth response of Pinus ponderosa seedlings and mature tree branches to acid rain and ozone exposure

    SciTech Connect

    Anderson, P.D.; Houpis, J.L.J.; Helms, J.A.

    1994-10-01

    Forests of the central and southern Sierra Nevada in California have been subjected to chronic damage by ozone and other atmospheric pollutants for the past several decades. Until recently, pollutant exposure of northern Sierra Nevada forests has been mild but increasing population and changes in land use throughout the Sacramento Valley and Sierra Nevada foothills may lead to increased pollutant damage in these forests. Although, better documented in other regions of the United States, little is known regarding the potential for acidic precipitation damage to Sierra Nevada forests. Only recently have studies directed towards understanding the potential interactive effects of ozone and acidic precipitation been undertaken. A key issue in resolving potential regional impacts of pollutants on forests is the extent to which research results can be scaled across genotypes and life-stages. Most of the pollution research to date has been performed using seedlings with varying degrees of genetic control. It is important to determine if the results obtained in such studies can be extrapolated to mature trees and to different genetic sources. In this paper, we present results from a one-year study examining the interactive effects of foliar exposure to acidic rain and ozone on the growth of ponderosa pine (Pinus ponderosa), a conifer known to be sensitive to ozone. The response to pollutants is characterized for both seedlings and mature tree branches of three genotypes grown in a common environment.

  4. Providing perspective for interpreting cardiovascular mortality risks associated with ozone exposures.

    PubMed

    Petito Boyce, Catherine; Goodman, Julie E; Sax, Sonja N; Loftus, Christine T

    2015-06-01

    When identifying standards for air pollutants based on uncertain evidence, both science and policy judgments play critical roles. Consequently, critical contextual factors are important for understanding the strengths, limitations, and appropriate interpretation of available science, and potential benefits of risk mitigation alternatives. These factors include the relative magnitude and certainty of the risks posed by various factors and the impacts of other risk factors on air pollutant epidemiology study findings. This commentary explores ozone's status as a risk factor for cardiovascular mortality in contrast with decades of strong and consistent evidence for other established risk factors. By comparison, the ozone evidence is less conclusive, more heterogeneous, and subject to substantial uncertainty; ozone's potential effects, if any, are small and challenging to discern. Moreover, the absence of a demonstrated causal relationship calls into question efforts to quantify cardiovascular mortality risks attributed to ozone exposures on a population level and highlights the need to explicitly acknowledge this uncertainty if such calculations are performed. These concerns are relevant for other similar policy contexts - where multiple established risk factors contribute to the health impact of interest; exposure-effect associations are relatively small, weak, and uncertain; and a causal relationship has not been clearly established. PMID:25817736

  5. Change in Negative Cognitions Associated with PTSD Predicts Symptom Reduction in Prolonged Exposure

    PubMed Central

    Zalta, Alyson K.; Gillihan, Seth J.; Fisher, Aaron J.; Mintz, Jim; McLean, Carmen P.; Yehuda, Rachel; Foa, Edna B.

    2014-01-01

    Objective The goal of the current study was to examine mechanisms of change in Prolonged Exposure (PE) therapy for post-traumatic stress disorder (PTSD). Emotional Processing Theory of PTSD proposes that disconfirmation of erroneous cognitions associated with PTSD is a central mechanism in PTSD symptom reduction; but to date, the causal relationship between change in pathological cognitions and change in PTSD severity has not been established. Method Female sexual or nonsexual assault survivors (N = 64) with a primary diagnosis of PTSD received 10 weekly sessions of PE. Self-reported PTSD symptoms, depression symptoms, and PTSD-related cognitions were assessed at pre-treatment, each of the 10 PE treatment sessions, and post-treatment. Results Lagged mixed-effect regression models indicated that session-to-session reductions in PTSD-related cognitions drove successive reductions in PTSD symptoms. By contrast, the reverse effect of PTSD symptom change on change in cognitions was smaller and did not reach statistical significance. Similarly, reductions in PTSD-related cognitions drove successive reductions in depression symptoms whereas the reverse effect of depression symptoms on subsequent cognition change was smaller and not significant. Notably, the relationships between changes in cognitions and PTSD symptoms were stronger than the relationships between changes in cognitions and depression symptoms. Conclusions To our knowledge, this is the first study to establish change in PTSD-related cognitions as a central mechanism of PE treatment. These findings are consistent with Emotional Processing Theory and have important clinical implications for the effective implementation of PE. PMID:24188512

  6. Transmitter secretion in the frog neuromuscular synapse after prolonged exposure to calcium-free solutions.

    PubMed

    Zefirov, A L; Mukhamedzyanov, R D; Minlebaev, M G; Cheranov, S Yu; Abdrakhmanov, M M; Grigor'ev, P N

    2003-07-01

    Experiments on neuromuscular synapses from frog skin/chest muscle preparations in conditions of extracellular recording addressed changes in the spontaneous and evoked transmitter secretion after long-term (1.5-6 h) maintenance of preparations in calcium-free solution containing EGTA. Use of three microelectrodes for recording of single-quantum postsynaptic signals showed that calcium-free solution altered the characteristic topography of transmitter secretion in nerve terminals, with widening and fusion of groups of transmitter release. These changes persisted after preparations were returned to the initial solution. These data suggest that calcium-free solutions lead to disorganization of the active zones of nerve endings, At initially low extracellular Ca ion concentrations (0.15-0.4 mM), disorganization of active zones induced by prolonged maintenance of preparations in calcium-free solutions led to decreases in the mean amplitude of endplate currents (EPC) because of decreases in their quantum composition, increases in the time course of transmitter secretion, and decreases in the frequency of miniature endplate currents. The relationship between quantum composition of EPC and the extracellular Ca ion concentration showed a sharp displacement towards higher concentrations, without significant changes in the slope of the relationship. At high initial Ca concentrations (1.8 mM), long-term exposure to calcium-free solutions led to a less marked decrease in EPC amplitude. It is suggested that the extra- and intracellular Ca ion concentrations support the maintenance of the characteristic morphofunctional organization of the apparatus responsible for transmitter secretion in frog nerve endings. Disorganization of the active zones leads to disruption of elements involved in transmitter secretion and decreases in the efficiency of secretion.

  7. Nutritional considerations during prolonged exposure to a confined, hyperbaric, hyperoxic environment: recommendations for saturation divers.

    PubMed

    Deb, S K; Swinton, P A; Dolan, E

    2016-01-01

    Saturation diving is an occupation that involves prolonged exposure to a confined, hyperoxic, hyperbaric environment. The unique and extreme environment is thought to result in disruption to physiological and metabolic homeostasis, which may impact human health and performance. Appropriate nutritional intake has the potential to alleviate and/or support many of these physiological and metabolic concerns, whilst enhancing health and performance in saturation divers. Therefore, the purpose of this review is to identify the physiological and practical challenges of saturation diving and consequently provide evidence-based nutritional recommendations for saturation divers to promote health and performance within this challenging environment. Saturation diving has a high-energy demand, with an energy intake of between 44 and 52 kcal/kg body mass per day recommended, dependent on intensity and duration of underwater activity. The macronutrient composition of dietary intake is in accordance with the current Institute of Medicine guidelines at 45-65 % and 20-35 % of total energy intake for carbohydrate and fat intake, respectively. A minimum daily protein intake of 1.3 g/kg body mass is recommended to facilitate body composition maintenance. Macronutrient intake between individuals should, however, be dictated by personal preference to support the attainment of an energy balance. A varied diet high in fruit and vegetables is highly recommended for the provision of sufficient micronutrients to support physiological processes, such as vitamin B12 and folate intake to facilitate red blood cell production. Antioxidants, such as vitamin C and E, are also recommended to reduce oxidised molecules, e.g. free radicals, whilst selenium and zinc intake may be beneficial to reinforce endogenous antioxidant reserves. In addition, tailored hydration and carbohydrate fueling strategies for underwater work are also advised. PMID:26744625

  8. Arsenic Exposure from Drinking Water and QT-Interval Prolongation: Results from the Health Effects of Arsenic Longitudinal Study

    PubMed Central

    Wu, Fen; Parvez, Faruque; Ahmed, Alauddin; Eunus, Mahbub; McClintock, Tyler R.; Patwary, Tazul Islam; Islam, Tariqul; Ghosal, Anajan Kumar; Islam, Shahidul; Hasan, Rabiul; Levy, Diane; Sarwar, Golam; Slavkovich, Vesna; van Geen, Alexander; Graziano, Joseph H.

    2013-01-01

    Background: Arsenic exposure from drinking water has been associated with heart disease; however, underlying mechanisms are uncertain. Objective: We evaluated the association between a history of arsenic exposure from drinking water and the prolongation of heart rate–corrected QT (QTc), PR, and QRS intervals. Method: We conducted a study of 1,715 participants enrolled at baseline from the Health Effects of Arsenic Longitudinal Study. We assessed the relationship of arsenic exposure in well water and urine samples at baseline with parameters of electrocardiogram (ECG) performed during 2005–2010, 5.9 years on average since baseline. Results: The adjusted odds ratio (OR) for QTc prolongation, defined as a QTc ≥ 450 msec in men and ≥ 460 msec in women, was 1.17 (95% CI: 1.01, 1.35) for a 1-SD increase in well-water arsenic (108.7 µg/L). The positive association appeared to be limited to women, with adjusted ORs of 1.24 (95% CI: 1.05, 1.47) and 1.24 (95% CI: 1.01, 1.53) for a 1-SD increase in baseline well-water and urinary arsenic, respectively, compared with 0.99 (95% CI: 0.73, 1.33) and 0.86 (95% CI: 0.49, 1.51) in men. There were no apparent associations of baseline well-water arsenic or urinary arsenic with PR or QRS prolongation in women or men. Conclusions: Long-term arsenic exposure from drinking water (average 95 µg/L; range, 0.1–790 µg/L) was associated with subsequent QT-interval prolongation in women. Future longitudinal studies with repeated ECG measurements would be valuable in assessing the influence of changes in exposure. PMID:23384555

  9. Respiratory responses of subjects with allergic rhinitis to ozone exposure and their relationship to nonspecific airway reactivity

    SciTech Connect

    McDonnell, W.F.; Horstman, D.H.; Abdul-Salaam, S.; Raggio, L.J.; Green, J.A.

    1987-12-01

    Ozone exposure in man produces changes in respiratory function and symptoms. There is a large degree of unexplained intersubject variability in the magnitude of these responses. There is concern that individuals with chronic respiratory diseases may also be more responsive to ozone than normal individuals. The purpose of this study was to describe the responses of subjects with allergic rhinitis to ozone exposure and to compare these responses to those previously observed in normal individuals. A further purpose was to measure the association of baseline nonspecific airway reactivity with changes in lung function and respiratory symptoms following ozone exposure. A group of 26 nonasthmatic subjects with allergic rhinitis performed a bronchial inhalation challenge with histamine and subsequently underwent two hour exposures to both clean air and to 0.18 part per million ozone with alternating periods of rest and heavy exercise. The airway reactivity of this group of subjects was no greater than that of a comparable group of subjects without allergic rhinitis. The respiratory responses of these subjects to ozone exposure were similar to those previously reported for subjects without allergic rhinitis with the exception that the allergic rhinitis subjects appeared to have a modestly increased bronchoconstrictor response compared to normals. Furthermore, we observed no significant relationships between nonspecific airway reactivity and response to ozone as measured by changes in lung function or the induction of symptoms.

  10. Inflammatory Cytokines and White Blood Cell Counts Response to Environmental Levels of Diesel Exhaust and Ozone Inhalation Exposures

    EPA Science Inventory

    Epidemiological observations of urban inhalation exposures to diesel exhaust (DE) and ozone (O3) have shown pre-clinical cardiopulmonary responses in humans. Identifying the key biological mechanisms that initiate these health bioindicators is difficult due to variability in envi...

  11. Ozone exposure thresholds and foliar injury on forest plants in Switzerland.

    PubMed

    VanderHeyden, D; Skelly, J; Innes, J; Hug, C; Zhang, J; Landolt, W; Bleuler, P

    2001-01-01

    Canton Ticino in southern Switzerland is exposed to some of the highest concentrations of tropospheric ozone in Europe. During recent field surveys in Canton Ticino, foliar symptoms identical to those caused by ozone have been documented on native tree and shrub species. In Europe, the critical ozone level for forest trees has been defined at an AOT40 of 10 ppm.h O3 (10 ppm.h accumulated exposure of ozone over a threshold of 40 ppb) during daylight hours over a six-month growing season. The objective of this study was to determine the amount of ambient ozone required to induce visible foliar symptoms on various forest plant species in southern Switzerland. Species were grown within eight open-top chambers and four open plots at the Vivaio Lattecaldo Cantonal Forest Nursery in Ticino, Switzerland. Species differed significantly in terms of the ppb.h exposures needed to cause visible symptoms. The most to least symptomatic species grown within open-plots in this study rank as Prunus serotina, Salix viminalis, Vibrnum lantana, Rhamnus cathartica, Betula pendula, Rumex obtusifolius, Sambucus racemosa, Morus nigra, Prunus avium, Fraxinus excelsior, Rhamnus frangula, Alnus viridis, Fagus sylvatica and Acer pseudoplatanus. Similar rankings were obtained in the non-filtered chamber plots. The ranking of species sensitivity closely follows AOT values for the occurrence of initial symptoms and symptom progression across the remainder of the exposure season. Species that first showed evidence of foliar injury also demonstrated the most sensitivity throughout the growing season, with symptoms rapidly advancing over ca. 25-30% of the total plant leaf surfaces by the end of the observation period. Conversely, those species that developed symptoms later in the season had far less total injury to plant foliage by the end of the observation period (1.5 to < 5% total leaf area injured). The current European ambient ozone standard may be insufficient to protect native plant species

  12. Ozone exposure thresholds and foliar injury on forest plants in Switzerland.

    PubMed

    VanderHeyden, D; Skelly, J; Innes, J; Hug, C; Zhang, J; Landolt, W; Bleuler, P

    2001-01-01

    Canton Ticino in southern Switzerland is exposed to some of the highest concentrations of tropospheric ozone in Europe. During recent field surveys in Canton Ticino, foliar symptoms identical to those caused by ozone have been documented on native tree and shrub species. In Europe, the critical ozone level for forest trees has been defined at an AOT40 of 10 ppm.h O3 (10 ppm.h accumulated exposure of ozone over a threshold of 40 ppb) during daylight hours over a six-month growing season. The objective of this study was to determine the amount of ambient ozone required to induce visible foliar symptoms on various forest plant species in southern Switzerland. Species were grown within eight open-top chambers and four open plots at the Vivaio Lattecaldo Cantonal Forest Nursery in Ticino, Switzerland. Species differed significantly in terms of the ppb.h exposures needed to cause visible symptoms. The most to least symptomatic species grown within open-plots in this study rank as Prunus serotina, Salix viminalis, Vibrnum lantana, Rhamnus cathartica, Betula pendula, Rumex obtusifolius, Sambucus racemosa, Morus nigra, Prunus avium, Fraxinus excelsior, Rhamnus frangula, Alnus viridis, Fagus sylvatica and Acer pseudoplatanus. Similar rankings were obtained in the non-filtered chamber plots. The ranking of species sensitivity closely follows AOT values for the occurrence of initial symptoms and symptom progression across the remainder of the exposure season. Species that first showed evidence of foliar injury also demonstrated the most sensitivity throughout the growing season, with symptoms rapidly advancing over ca. 25-30% of the total plant leaf surfaces by the end of the observation period. Conversely, those species that developed symptoms later in the season had far less total injury to plant foliage by the end of the observation period (1.5 to < 5% total leaf area injured). The current European ambient ozone standard may be insufficient to protect native plant species

  13. The effect of ozone exposure on the dispersion of inhaled aerosol boluses in healthy human subjects

    SciTech Connect

    Keefe, M.J.; Bennett, W.D.; DeWitt, P.; Seal, E.; Strong, A.A.; Gerrity, T.R. )

    1991-07-01

    Acute exposure of humans to low levels of ozone are known to cause decreases in FVC and increases in SRaw. These alterations in lung function do not, however, elucidate the potential for acute small airway responses. In this study we employed a test of aerosol dispersion to examine the potential effects of ozone on small airways in humans. Twenty-two healthy nonsmoking male volunteers were exposed to 0.4 ppm ozone for 1 h while exercising at 20 L/min/m2 body surface area. Before and immediately after exposure, tests of spirometry (FVC, FEV1, and FEF25-75) and plethysmography (Raw and SRaw) were performed. Subjects also performed an aerosol dispersion test before and after exposure. Each test involved a subject inhaling five to seven breaths of a 300-ml bolus of a 0.5 micron triphenyl phosphate aerosol injected into a 2-L tidal volume. The bolus was injected into the tidal breath at three different depths: at Depth A the bolus was injected after 1.6 L of clean air were inhaled from FRC, at Depth B after 1.2 L, and at Depth C after 1.2 L but with inhalation beginning from RV. The primary measure of bolus dispersion was the expired half-width (HW). Secondary measures were the ratio (expressed as percent) of peak exhaled aerosol concentration to peak inhaled concentration (PR), shift in the median bolus volume between inspiration and expiration (VS), and percent of total aerosol recovered (RC). Changes in pulmonary function after ozone exposure were consistent with previous findings.

  14. Effect of ozone exposure on the dispersion of inhaled aerosol boluses in healthy human subjects

    SciTech Connect

    Keefe, M.J.; Bennett, W.D.; Dewitt, P.; Seal, E.; Strong, A.A.

    1990-12-06

    Acute exposure of humans to low levels of ozone are known to cause decreases FVC and increases sRaw. These alterations in lung function do not, however, elucidate the potential for acute small airways responses. In the study the authors employed a test of aerosol dispersion to examine the potential effects of ozone on small airways in humans. Twenty-two healthy non-smoking male volunteers were exposed to 0.4 ppm ozone for one hour while exercising at 20 l/min/m{sup 2} (BSA). Prior to and immediately following exposure, tests of spirometry (FVC, FEV1, and FEF25-75) and plethysmography (Raw and sRaw) were performed. Subjects also performed an aerosol dispersion test before and after exposure. Each test involved a subject inhaling five to seven breaths of a 300 ml bolus of a 0.5 micrometers triphenyl phosphate (TPP) aerosol injected into a 2 liters tidal volume. The bolus was injected into the tidal breath at three different depths: at depth A the bolus was injected after 1.6 liters of clean air was inhaled from FRC; at depth B after 1.2 liters; and at depth C after 1.2 liters but with inhalation beginning from RV. The primary measure of bolus dispersion was the expired half-width (HW).

  15. Acute ozone exposure increases plasma prostaglandin F2 alpha in ozone-sensitive human subjects

    SciTech Connect

    Schelegle, E.S.; Adams, W.C.; Giri, S.N.; Siefkin, A.D.

    1989-07-01

    Twenty O/sub 3/-sensitive and /sup 2/O O/sub 3/-nonsensitive subjects participated in a study to investigate the effects of disparate O/sub 3/ sensitivity on plasma prostaglandin F2 alpha responses consequent to exposure to ambient O3 concentrations. Subjects were selected from a pool of 75 normal healthy college-aged males who had been previously exposed to 0.35 ppm O3 for 1 h at an exercising VE of 60 L/min. The selection criterion used was the observed decrement in FEV1 after the O/sub 3/ exposure: O/sub 3/-sensitive, FEV1 decrement greater than 24%; O/sub 3/-nonsensitive, FEV1 decrement less than 11%. Each subject was exposed to filtered air and to 0.20 and 0.35 ppm O/sub 3/ for 80 min while exercising at a VE of 50 L/min. These experimental protocols were divided into two 40-min sessions separated by a period of 4 to 10 min. PGF2 alpha, FVC, FEV1, and FEF25-75 were evaluated before, during, and after each protocol. SGaw and Vtg were measured before and after each protocol. Plasma PGF2 alpha was significantly increased in the O/sub 3/-sensitive group during and after the 0.35-ppm O/sub 3/ exposure.

  16. Effect of acute ozone exposure on the proteinase-antiproteinase balance in the rat lung

    SciTech Connect

    Pickrell, J.A.; Gregory, R.E.; Cole, D.J.; Hahn, F.F.; Henderson, R.F.

    1987-04-01

    Lung disease may result from a persisting proteinase excess or a depletion of antiproteinase in pulmonary parenchyma. We investigated the in vivo effect of a 48-hr exposure to ozone at 0.5, 1.0, or 1.5 ppm on proteinase and antiproteinase activity of rat lungs. Elastase inhibitory capacities of serum, lung tissue, and airway washings were measured as indicators of antielastase activity. Trypsin inhibitory capacity was measured using an esterolytic procedure. Proteinase was measured as radioactive release from a /sup 14/C-globin substrate. The 48-hr exposures to O/sub 3/ at levels up to 1 ppm produced concentration-dependent decreases of 35-80% of antiproteinase activities in serum and in lung tissue. However, exposure to 1.5 ppm O/sub 3/ resulted in no decrease in antiproteinase activities. Acid proteinase activities (pH 4.2) were increased 65-120% by exposure to 1 or 1.5 ppm O/sub 3/, which correlated with inflammatory cells noted histologically. At 1.5 ppm O/sub 3/, pulmonary edema and hemorrhage were noted in histologic sections. These changes led to a flooding of the alveoli with up to 40 times normal protein levels and a greater than fivefold increase in airway antiproteinase. These data suggest that serum and soluble lung tissue antiproteinase activity decreased upon exposure to low levels of ozone. However, if O/sub 3/ exposure is high enough to produce pulmonary hemorrhage, antiproteinase may increase following serum exudation. These changes may be important in the development of ozone-induced lung diseases, especially emphysema.

  17. Effect of ozone exposure on the electrical characteristics of high-purity, large-diameter semiconducting carbon nanotubes.

    PubMed

    Gao, Jia; Loo, Yueh-Lin

    2014-06-14

    In this study, we have elucidated the interactions between ozone and carbon nanotubes by monitoring the characteristics of field-effect transistors based on polymer-sorted, large-diameter semiconducting carbon nanotubes. The drain-source current of these transistors initially increases with ozone exposure and then it progressively decreases with increasing exposure beyond 3 min. This non-monotonic dependence of the drain-source current can be ascribed to two competing processes. At short ozone exposure, p-doping of carbon nanotubes dominates; the drain-source current thus increases as a result of increasing hole concentration. This effect is most evidenced in a progressive threshold voltage shift towards positive voltages with increasing exposure to ozone. At extended ozone exposure, chemical oxidation of carbon nanotubes instead dominates. The drain-source current decreases as a result of decreasing hole mobility. This effect manifests itself in a monotonic decrease in the mobility of these devices as a function of ozone exposure. PMID:24760174

  18. Ozone

    SciTech Connect

    Not Available

    1988-06-01

    The author discusses the debate over whether concern about a hole in the ozone layer in Antarctic is real or science fiction. There is a growing consensus that efforts must be taken to protect the ozone layer. The issue now is not whether chlorofluorocarbons (CFCs) should be controlled and regulated but how much and how soon. The United States has urged that the production of dangerous CFCs, and any other chemicals that affect the ozone layer, be restricted immediately to current levels and that their use be reduced 95 percent over the next decade. The American position was too strong for many European nations and the Japanese. Negotiations at an international conference on the matter broke down. The breakdown is due in part to a more acute concern for environmental matters in the United States than exists in many countries. Meanwhile CFCs are linked to another environmental problem that equally threatens the world - the Greenhouse Effect. The earth is in a natural warming period, but man could be causing it to become even warmer. The Greenhouse Effect could have a catastrophic impact on mankind, although nothing has been proven yet.

  19. A Genome-Wide mRNA Expression Profile in Caenorhabditis elegans under Prolonged Exposure to 1750MHz Radiofrequency Fields

    PubMed Central

    Gao, Dawen; Yu, Zhoulong; Wu, Tongning; Zhang, Chenggang

    2016-01-01

    Objective C. elegans has been used as a biomonitor for microwave-induced stress. However, the RF (radiofrequency) fields that have been used in previous studies were weak (≤1.8W/kg), and the bio-effects on C. elegans were mostly negative or ambiguous. Therefore, this study used more intense RF fields (SAR = 3W/kg) and longer time course of exposure (60h at 25°C, L1 stage through adult stage) to investigate the biological consequences of 1750 MHz RF fields in wild-type worms. Methods The growth rates and lifespans of RF-exposure group and the control group were carefully recorded. RNA samples were collected at L4 (35h) and gravid adult (50h) stages for further high-throughput sequencing, focusing on differences between the RF-exposure and the sham control groups. Results The RF-exposed and sham control groups developed at almost the same rate and had similar longevity curves. In L4 stage worms, 94 up-regulated and 17 down-regulated genes were identified, while 186 up-regulated and 3 down-regulated genes were identified in adult stage worms. GO analysis showed that the differentially expressed genes at 35h were associated with growth, body morphogenesis and collagen and cuticle-based development. Genes that were linked to growth rate and reproductive development were differentially expressed at 50h. Some embryonic and larval development genes in the offspring were also differentially expressed at 50h. Ten genes were differentially expressed at both 35h and 50h, most of which were involved in both embryonic and larval developmental processes. Although prolonged RF fields did not induce significant temperature increase in RF exposure groups, the temperature inside worms during exposure was unknown. Conclusions No harmful effects were observed in prolonged exposure to 1750 MHz RF fields at SAR of 3W/kg on development and longevity of C. elegans. Although some differentially expressed genes were found after prolonged RF exposure, these differences were ascribed to

  20. Activity of ozonated water and ozone against Staphylococcus aureus and Pseudomonas aeruginosa biofilms

    PubMed Central

    Bialoszewski, Dariusz; Pietruczuk-Padzik, Anna; Kalicinska, Agnieszka; Bocian, Ewa; Czajkowska, Magdalena; Bukowska, Bozena; Tyski, Stefan

    2011-01-01

    Summary Background The known bactericidal properties of ozone have not been checked in relation to its action on bacterial biofilms. This is especially true of ozonated fluids. The aim of this study was to investigate the bactericidal activity of ozonated water and that of a mixture of ozone and oxygen against biofilms. Material/Methods Eighteen clinical strains of Staphylococcus aureus and Pseudomonas aeruginosa exhibiting various levels of antibiotic sensitivity were investigated. Bacteria were cultured in biofilm form on polystyrene titration plates for periods of 2 to 72 hours. The biofilms formed in this way were exposed to in statu nascendi ozonated water produced in a prototype device that had been tested in clinical conditions, or to a mixture of oxygen and ozone generated in the same device. Live cells in the biofilm were stained with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide solution. The degree of reduction of viable bacteria following ozone exposure was determined. Results Ozonated water was found to be an effective bactericidal agent against biofilms after as little as 30 seconds of exposure, while the bactericidal activity of the ozone-oxygen solution was much lower. Prolongation of the duration of biofilm exposure to the gaseous disinfectant to 40 minutes led to a reduction in the viable cell count, which nevertheless remained high. Conclusions Unlike the ozone-oxygen mixture, ozonated water effectively destroys bacterial biofilms in vitro. PMID:22037737

  1. Potential Adverse Effects of Prolonged Sevoflurane Exposure on Developing Monkey Brain: From Abnormal Lipid Metabolism to Neuronal Damage.

    PubMed

    Liu, Fang; Rainosek, Shuo W; Frisch-Daiello, Jessica L; Patterson, Tucker A; Paule, Merle G; Slikker, William; Wang, Cheng; Han, Xianlin

    2015-10-01

    Sevoflurane is a volatile anesthetic that has been widely used in general anesthesia, yet its safety in pediatric use is a public concern. This study sought to evaluate whether prolonged exposure of infant monkeys to a clinically relevant concentration of sevoflurane is associated with any adverse effects on the developing brain. Infant monkeys were exposed to 2.5% sevoflurane for 9 h, and frontal cortical tissues were harvested for DNA microarray, lipidomics, Luminex protein, and histological assays. DNA microarray analysis showed that sevoflurane exposure resulted in a broad identification of differentially expressed genes (DEGs) in the monkey brain. In general, these genes were associated with nervous system development, function, and neural cell viability. Notably, a number of DEGs were closely related to lipid metabolism. Lipidomic analysis demonstrated that critical lipid components, (eg, phosphatidylethanolamine, phosphatidylserine, and phosphatidylglycerol) were significantly downregulated by prolonged exposure of sevoflurane. Luminex protein analysis indicated abnormal levels of cytokines in sevoflurane-exposed brains. Consistently, Fluoro-Jade C staining revealed more degenerating neurons after sevoflurane exposure. These data demonstrate that a clinically relevant concentration of sevoflurane (2.5%) is capable of inducing and maintaining an effective surgical plane of anesthesia in the developing nonhuman primate and that a prolonged exposure of 9 h resulted in profound changes in gene expression, cytokine levels, lipid metabolism, and subsequently, neuronal damage. Generally, sevoflurane-induced neuronal damage was also associated with changes in lipid content, composition, or both; and specific lipid changes could provide insights into the molecular mechanism(s) underlying anesthetic-induced neurotoxicity and may be sensitive biomarkers for the early detection of anesthetic-induced neuronal damage.

  2. Comparison of seasonal variations of ozone exposure and fluxes in a Mediterranean Holm oak forest between the exceptionally dry 2003 and the following year.

    PubMed

    Gerosa, Giacomo; Finco, Angelo; Mereu, Simone; Vitale, Marcello; Manes, Fausto; Denti, Antonio Ballarin

    2009-05-01

    Ozone and energy fluxes have been measured using the eddy covariance technique, from June to December 2004 in Castelporziano near Rome (Italy), and compared to similar measurements made in the previous year. The studied ecosystem consisted in a typical Mediterranean Holm oak forest. Stomatal fluxes have been calculated using the resistance analogy and by inverting the Penmann-Monteith equation. Results showed that the average stomatal contribution accounts for 42.6% of the total fluxes. Non-stomatal deposition proved to be enhanced by increasing leaf wetness and air humidity during the autumnal months. From a comparison of the two years, it can be inferred that water supply is the most important limiting factor for ozone uptake and that prolonged droughts alter significantly the stomatal conductance, even 2 months after the soil water content is replenished. Ozone exposure, expressed as AOT40, behaves similarly to the cumulated stomatal flux in dry conditions whereas a different behaviour for the two indices appears in wet autumnal conditions. A difference also occurs between the two years.

  3. Autonomic Effects of Controlled Fine Particulate Exposure in Young Healthy Adults: Effect Modification by Ozone

    PubMed Central

    Fakhri, Asghar A.; Ilic, Ljubomir M.; Wellenius, Gregory A.; Urch, Bruce; Silverman, Frances; Gold, Diane R.; Mittleman, Murray A.

    2009-01-01

    Background Human controlled-exposure studies have assessed the impact of ambient fine particulate matter on cardiac autonomic function measured by heart rate variability (HRV), but whether these effects are modified by concomitant ozone exposure remains unknown. Objective In this study we assessed the impact of O3 and particulate matter exposure on HRV in humans. Methods In a crossover design, 50 subjects (19–48 years of age) were randomized to 2-hr controlled exposures to filtered air (FA), concentrated ambient particles (CAPs), O3, or combined CAPs and ozone (CAPs + O3). The primary end point was change in HRV between the start and end of exposure. Secondary analyses included blood pressure (BP) responses, and effect modification by asthmatic status. Results Achieved mean CAPs and O3 exposure concentrations were 121.6 ± 48.0 μg/m3 and 113.9 ± 6.6 ppb, respectively. In a categorical analysis, exposure had no consistent effect on HRV indices. However, the dose–response relationship between CAPs mass concentration and HRV indices seemed to vary depending on the presence of O3. This heterogeneity was statistically significant for the low-frequency component of HRV (p = 0.02) and approached significance for the high-frequency component and time-domain measures of HRV. Exposure to CAPs + O3 increased diastolic BP by 2.0 mmHg (SE, 1.2; p = 0.02). No other statistically significant changes in BP were observed. Asthmatic status did not modify these effects. Conclusion The potentiation by O3 of CAPs effects on diastolic BP and possibly HRV is of small magnitude in young adults. Further studies are needed to assess potential effects in more vulnerable populations. PMID:19672410

  4. Subacute Inhalation Exposure to Ozone Induces Systemic Inflammation but not Insulin Resistance in a Diabetic Mouse Model

    PubMed Central

    Ying, Zhekang; Allen, Katryn; Zhong, Jixin; Chen, Minjie; Williams, Keisha M.; Wagner, James G.; Lewandowski, Ryan; Sun, Qinghua; Rajagopalan, Sanjay; Harkema, Jack R.

    2016-01-01

    Epidemiological studies suggest that diabetics may be more susceptible to the adverse health effects from exposure to high ambient concentrations of ozone, the primary oxidant gas in photochemical smog. While increased morbidity and mortality from ozone inhalation has been linked to disruption of normal cardiovascular and airway functions, potential effects on glucose and insulin homeostasis are not understood. We tested the hypothesis that ozone exposure would worsen metabolic homeostasis in KKAy mice, a genetic diabetic animal model. Male KKAy mice were exposed to 0.5 ppm ozone for thirteen consecutive weekdays, and then assessed for airway, adipose and systemic inflammation, glucose homeostasis, and insulin signaling. Ozone exposure caused increased plasma TNFα, as well as expression of VCAM-1, iNOS and IL-6 in both pulmonary and adipose tissues. Pro-inflammatory CD11b+Gr-1lo7/4hi macrophages were increased 200% in adipose tissue but unchanged in blood. Interestingly, glucose levels were not significantly different in the insulin tolerance test between air and ozone-expose mice, whereas fasting insulin levels and HOMA-IR in ozone-exposed animals were significantly reduced. These changes were accompanied by increased insulin signaling in skeletal muscle and liver, but not adipose tissues. Ozone also caused decreases in body weight and plasma leptin. Our results show that in addition to marked local and systemic inflammation, ozone increases insulin sensitivity that may be related to weight loss/leptin sensitization-dependent mechanisms in KKAy mice, warranting further study on the role of hyperglycemia in mediating cardiometabolic effects of ozone inhalation. PMID:26986950

  5. Subacute inhalation exposure to ozone induces systemic inflammation but not insulin resistance in a diabetic mouse model.

    PubMed

    Ying, Zhekang; Allen, Katryn; Zhong, Jixin; Chen, Minjie; Williams, Keisha M; Wagner, James G; Lewandowski, Ryan; Sun, Qinghua; Rajagopalan, Sanjay; Harkema, Jack R

    2016-01-01

    Epidemiological studies suggest that diabetics may be more susceptible to the adverse health effects from exposure to high ambient concentrations of ozone, the primary oxidant gas in photochemical smog. While increased morbidity and mortality from ozone inhalation has been linked to disruption of normal cardiovascular and airway functions, potential effects on glucose and insulin homeostasis are not understood. We tested the hypothesis that ozone exposure would worsen metabolic homeostasis in KKAy mice, a genetic diabetic animal model. Male KKAy mice were exposed to 0.5 ppm ozone for 13 consecutive weekdays, and then assessed for airway, adipose and systemic inflammation, glucose homeostasis, and insulin signaling. Ozone exposure increased plasma TNFα, as well as expression of VCAM-1, iNOS and IL-6 in both pulmonary and adipose tissues. Pro-inflammatory CD11b(+)Gr-1(lo)7/4(hi) macrophages were increased by 200% in adipose tissue, but unchanged in blood. Interestingly, glucose levels were not significantly different in the insulin tolerance test between air- and ozone-exposed mice, whereas fasting insulin levels and HOMA-IR in ozone-exposed animals were significantly reduced. These changes were accompanied by increased insulin signaling in skeletal muscle and liver, but not adipose tissues. Ozone also caused decrease in body weight and plasma leptin. Our results show that in addition to marked local and systemic inflammation, ozone increases insulin sensitivity that may be related to weight loss/leptin sensitization-dependent mechanisms in KKAy mice, warranting further study on the role of hyperglycemia in mediating cardiometabolic effects of ozone inhalation. PMID:26986950

  6. Exposure-plant response of ambient ozone over the tropical Indian region

    NASA Astrophysics Data System (ADS)

    Roy, S.; Beig, G.; Ghude, S.

    2009-02-01

    A high resolution regional chemistry-transport model has been used to study the distribution of exposure-plant response index (AOT40, Accumulated exposure Over a Threshold of 40 ppb, expressed as ppb h) over the Indian geographical region for the year 2003 as case study. The directives on ozone pollution in ambient air provided by United Nations Economic Commission for Europe (UNECE) and World Health Organization (WHO) for vegetation protection (AOT40) have been used to assess the air quality. A substantial temporal and spatial variation in AOT40 values has been observed across the Indian region. Large areas of India show ozone values above the AOT40 threshold limit (3000 ppb h for 3 months). Simulated AOT40 values are found to be substantially higher throughout the year over the most fertile Indo-Gangetic plains than the other regions of India, which can have an adverse effect on plants and vegetation in this region. The observed monthly AOT40 values reported from an Indian station, agree reasonably well with model simulated results. We find that the simulated AOT40 target values for protection of vegetation is exceeded even in individual months, especially during November and April. Necessary and effective emission reduction strategies are therefore required to be developed in order to curb the surface level ozone pollution to protect the vegetation from further damage in India whose economy is highly dependent on agricultural sector and may influence the global balance.

  7. US Environmental Protection Agency's Ozone Epidemiology Research Program: A strategy for assessing the effects of ambient ozone exposure upon morbidity in exposed populations

    SciTech Connect

    McDonnell, W.F.; Zenick, H.; Hayes, C.G. )

    1993-07-01

    The Clean Air Act Amendments of 1990 mandate a future reduction of ambient ozone levels in many areas of the country, the cost of which will be great. In order to assess the current public health burden of ambient ozone exposure and to provide information for assessment of potential health benefits of improved air quality, the Health Effects Research Laboratory of the U.S. EPA has undertaken an Ozone Epidemiology Research Program. The research strategy which will guide this scientific program is described in this paper. Criteria for selection of important research questions as well as issues which cut across all questions and study designs are discussed. In particular, this program emphasizes the study of effects which reflect morbidity in the population. The three questions identified as being of most immediate importance involve the relationship of short-term ambient ozone exposure to acute respiratory illness, the relationship of recurrent exposure to chronic respiratory disease, and the relationship of recurrent exposure to development of acute respiratory illness. Specific research approaches and initial projects to address these three questions are described.

  8. Characterization of anxiety-related responses in male rats following prolonged exposure to therapeutic doses of oral methylphenidate.

    PubMed

    Britton, Gabrielle B; Bethancourt, José A

    2009-10-01

    Increases in the rates of attention-deficit/hyperactivity disorder (ADHD) diagnosis and the prescribed use of methylphenidate (MPH) in recent years have raised concerns over the potential effects of early MPH exposure on brain structure and function in adulthood. Animal studies have shown that long-term MPH exposure can modify anxiety-related behaviors and related neural circuitry in adulthood. The present study employed a battery of behavioral tests and repeated testing to assess the long-term effects of MPH exposure on anxious responding. Male Wistar rats beginning on post-natal day 27 were exposed to 4 or 7 weeks of twice daily MPH administration at doses of 2, 3, or 5 mg/kg. MPH was administered orally and on weekdays only in order to approximate drug treatment in clinical populations. Behavioral testing began 18 days following the last drug administration. Our results indicate that prolonged oral MPH treatment at therapeutic doses has little or no enduring effects on anxious behaviors. However, a comparison of MPH groups that received treatment for 4 or 7 weeks suggests that the two treatment periods influenced anxious behaviors in observably different manners in adulthood; namely, a more prolonged period of exposure produced less anxiety relative to the shorter period of MPH exposure as indicated by behaviors in the light-dark transition, elevated plus-maze, and fear conditioning tests. These findings were interpreted as evidence of the importance of considering length of drug exposure in pre-clinical studies aimed at investigating the effects of MPH exposure in ADHD populations.

  9. Susceptibility to ozone-induced inflammation. II. Separate loci control responses to acute and subacute exposures

    SciTech Connect

    Kleeberger, S.R.; Levitt, R.C.; Zhang, L.Y. )

    1993-01-01

    We demonstrated previously that inbred strains of mice are differentially susceptible to acute (3 h) and subacute (48 h) exposures to 2 parts per million (ppm) ozone (O3) and 0.30 ppm O3, respectively. Genetic studies with O3-resistant C3H/HeJ and O3-susceptible C57BL/6J strains have indicated that susceptibility to each of these O3 exposures is under Mendelian (single gene) control. In the present study, we hypothesized that the same gene controls susceptibility to the airway inflammatory responses to 2 ppm and 0.30 ppm O3 exposures. To test this hypothesis, airway inflammation was induced in 10 BXH and 16 BXD recombinant inbred (RI) strains of mice by acute as well as subacute O3 exposures. Airway inflammation was assessed by counting the number of polymorphonuclear leukocytes (PMNs) in bronchoalveolar lavage (BAL) returns obtained immediately after 48-h subacute exposure to 0.30 ppm O3, or 6 h after 3 h acute exposure to 2 ppm O3. Each RI strain was classified as susceptible or resistant to each exposure, based on a comparison of mean numbers of PMNs with those of the respective progenitor strains. For each RI set, a phenotypic strain distribution pattern (SDP) was thus derived for each exposure regimen, and the SDPs were then compared for concordance. Among the BXH RI strains, 4 of 10 responded discordantly to the two exposures: 3 were susceptible to acute exposure and resistant to subacute exposure, whereas 1 was conversely susceptible. Among the BXD RI strains, 4 of 16 were discordant: 1 was susceptible to acute exposure, and resistant to subacute exposure, whereas 3 were conversely susceptible.

  10. Evaluation of effects of ozone exposure on influenza infection in mice using several indicators of susceptibility

    SciTech Connect

    Selgrade, M.K.; Illing, J.W.; Starnes, D.M.; Stead, A.G.; Menache, M.G.; Stevens, M.A.

    1988-07-01

    Mice were exposed to 1 ppm O3, 3 hr/day, for 5 consecutive days. Separate groups of mice were infected with influenza following each of the individual exposures. A twofold increase in the incidence of mortality and a 3-day decrease in mean survival time were observed in mice infected after the second exposure. There were no effects on percentage mortality or mean survival time due to exposure to 1 ppm O3 in mice infected after the first, third, fourth, or fifth exposure. When the exposure concentration was lowered to 0.5 ppm, there were no effects on mortality in mice infected after the second exposure. Five, daily, 3-hr exposures to 1 ppm O3 had no effect on virus titers in the lungs of mice infected after either the second or fifth exposure. In contrast, wet lung weights were significantly enhanced over infected air controls in mice infected after the second O3 exposure at both 1 and 0.5 ppm but not at 0.25 ppm exposure concentrations. This effect on lung wet weight was observed in mice infected with a dose of virus which produced 7-33% mortality in controls as well as in mice infected with a sublethal dose of virus. Histopathologic changes due to sublethal influenza infection, including nonsuppurative pneumonitis and necrosis, squamous metaplasia and hyperplasia of the epithelium lining the bronchi and bronchioles, were more severe in mice infected after the second of five, 1 ppm O3 exposure than in comparable air controls. Sublethal infection caused a loss of lung volume with secondary reduction in diffusing capability and homogenity of ventilation distribution. These latter two effects were also exacerbated in mice infected after the second of five, 1 ppm O3 exposures as compared to air controls. When mice were infected after the fifth, 1 ppm O3 exposure, there was no effect due to ozone on either lung wet weight or histopathology.

  11. Design of a citizen survey of forest plant injury caused by exposure to ozone

    SciTech Connect

    Morton, B.J.

    1994-12-31

    The North Carolina Environmental Defense Fund has designed a citizen-based survey of forest plant injury caused by exposure to ozone. The first, pilot survey will run for ten weeks in July, August, and September 1994. The surveyors will be trained laypersons who are donating their tie and effort. The scientific objective of the survey is to look for and collect evidence on the incidence and severity of ozone-injury to the leaves of plants and trees (seedling- and sapling-sized plants) in the forests of western North Carolina. The educational objective is to discuss the facts and meaning of air pollution problems in the southern Appalachian Mountains. The third and equally important objective involves policy dialogue: specifically, the objective is to motivate the surveyors to participate in local and regional forums at which mountain air pollution is on the agenda.

  12. Hepatic and intestine alterations in mice after prolonged exposure to low oral doses of Microcystin-LR.

    PubMed

    Sedan, Daniela; Laguens, Martín; Copparoni, Guido; Aranda, Jorge Oswaldo; Giannuzzi, Leda; Marra, Carlos Alberto; Andrinolo, Darío

    2015-09-15

    Oral intake of Microcystin-LR (MC-LR) is the principal route of exposure to this toxin, with prolonged exposure leading to liver damage of unspecific symptomatology. The aim of the present paper was therefore to investigate the liver and intestine damage generated by prolonged oral exposure to low MC-LR doses (50 and 100 μg MC-LR/kg body weight, administrated every 48 h during a month) in a murine model. We found alterations in TBARS, SOD activity and glutathione content in liver and intestine of mice exposed to both doses of MC-LR. Furthermore, the presence of MC-LR was detected in both organs. We also found hepatic steatosis (3.6 ± 0.6% and 15.3 ± 1.6%) and a decrease in intraepithelial lymphocytes (28.7 ± 5.0% and 44.2 ± 8.7%) in intestine of 50- and 100-μg MC-LR/kg treated animals, respectively. This result could have important implications for mucosal immunity, since intraepithelial lymphocytes are the principal effectors of this system. Our results indicate that prolonged oral exposure at 50 μg MC-LR/kg every 48 h generates significant damage not only in liver but also in intestine. This finding calls for a re-appraisal of the currently accepted NOAEL (No Observed Adverse Effect Level), 40 μg MC-LR/kg body weight, used to derive the guideline value for MC-LR in drinking water.

  13. Exposure-plant response of ambient ozone over the tropical Indian region

    NASA Astrophysics Data System (ADS)

    Roy, S. Deb; Beig, G.; Ghude, Sachin D.

    2009-07-01

    A high resolution regional chemistry-transport model has been used to study the distribution of exposure-plant response index (AOT40, Accumulated exposure Over a Threshold of 40 ppb, expressed as ppb h) over the Indian geographical region for the year 2003 as case study. The directives on ozone pollution in ambient air provided by United Nations Economic Commission for Europe (UNECE) and World Health Organization (WHO) for vegetation protection (AOT40) have been used to assess the air quality. A substantial temporal and spatial variation in AOT40 values has been observed across the Indian region. Large areas of India show ozone values above the AOT40 threshold limit (3000 ppb h for 3 months). Simulated AOT40 values are found to be substantially higher throughout the year over the most fertile Indo-Gangetic plains than the other regions of India, which can have an adverse effect on plants and vegetation in this region. The observed monthly AOT40 values reported from an Indian station, agree reasonably well with model simulated results. There is an underestimation of AOT40 in the model results during the periods of highest ozone concentration from December to March. We find that the simulated AOT40 target values for protection of vegetation is exceeded even in individual months, especially during November to April. Necessary and effective emission reduction strategies are therefore required to be developed in order to curb the surface level ozone pollution to protect the vegetation from further damage in India whose economy is highly dependent on agricultural sector and may influence the global balance.

  14. Phenological weighting of ozone exposures in the calculation of critical levels for wheat, bean and plantain.

    PubMed

    Soja, G; Barnes, J D; Posch, M; Vandermeiren, K; Pleijel, H; Mills, G

    2000-09-01

    This paper presents phenological weighting factors to be applied to AOT40 (accumulated ozone exposure above a threshold of 40 nl l(-1)) ozone exposure-response relationships for crops at different growth stages. The quantification of such factors represents a step-forward in the derivation of Level II critical levels for ozone. The weighting factors presented are derived from published literature on the sensitivity of wheat (Triticum aestivum), bean (Phaseolus vulgaris) and plantain (Plantago major) to ozone at different growth stages. Weighting functions were calculated using either multiple linear regression or the reciprocal residual mean square (RMS(-1)). The resulting weights were transformed into multiplication factors to be applied to the monthly AOT40 during the 3-month assessment period of critical level exceedance. Interspecific differences were too large to allow for the development of a unified weighting function for the three species considered. For wheat grain yield, the derived multiplication factors varied by almost four-fold (0.40, 1.06, 1.54), while those for bean pod yield varied by only about 25% (0.85, 1.01, 1.14). The available data for plantain were restricted to short-term studies conducted under controlled conditions. These data were not suitable for the derivation of weighting factors comparable to those derived for bean and wheat. Based on known differences in wheat development and phenology across Europe, the need for a geographic differentiation of the time period for the calculation of the critical level exceedances is also discussed and examples provided of the adoption of the derived weightings in the mapping of critical level exceedances. Differences between critical level exceedance maps using weighted and unweighted AOT40 calculations are discussed.

  15. Repeated laboratory ozone exposures of volunteer Los Angeles residents: an apparent seasonal variation in response

    SciTech Connect

    Linn, W.S.; Avol, E.L.; Shamoo, D.A.; Peng, R.C.; Valencia, L.M.; Little, D.E.; Hackney, J.D.

    1988-12-01

    This study was intended to help explain individual differences in susceptibility to irritant effects of ozone (O3), by determining whether prior ambient O3 exposures and/or recent acute respiratory illness modified response to laboratory O3 exposures. Response was measured in terms of lung function changes and irritant symptoms. Initially, 59 adult volunteer Los Angeles area residents underwent screening exposures in spring, before the season of frequent high ambient O3 levels. Unusually responsive and nonresponsive individuals (N = 12 and 13 respectively) underwent followup exposures in autumn (late in the high-O3 season) and in winter (low-O3 season). All exposures were to 0.18 ppm O3 for 2 hr with intermittent heavy exercise at 31 degrees C and 35% relative humidity. Nonresponders tended to remain nonresponsive throughout. In fall, responders had lost much of their reactivity, as if they had adapted to summer ambient O3 exposures. They did not regain reactivity by winter. Clinical laboratory findings suggestive of acute respiratory illness did not appear to correlate with O3 response. Eight responders and 9 nonresponders underwent another followup exposure in spring, about 1 yr after screening. By that time most responders had regained their reactivity; individual function changes were significantly correlated with changes 1 yr earlier. These results suggest that response to O3 is a persistent individual characteristic, but can be modified by repeated ambient exposures.

  16. Early Life Ozone Exposure Results in Dysregulated Innate Immune Function and Altered microRNA Expression in Airway Epithelium

    PubMed Central

    Gerriets, Joan E.; Wang, Theodore T.; Postlethwait, Edward M.; Evans, Michael J.; Fontaine, Justin H.; Miller, Lisa A.

    2014-01-01

    Exposure to ozone has been associated with increased incidence of respiratory morbidity in humans; however the mechanism(s) behind the enhancement of susceptibility are unclear. We have previously reported that exposure to episodic ozone during postnatal development results in an attenuated peripheral blood cytokine response to lipopolysaccharide (LPS) that persists with maturity. As the lung is closely interfaced with the external environment, we hypothesized that the conducting airway epithelium of neonates may also be a target of immunomodulation by ozone. To test this hypothesis, we evaluated primary airway epithelial cell cultures derived from juvenile rhesus macaque monkeys with a prior history of episodic postnatal ozone exposure. Innate immune function was measured by expression of the proinflammatory cytokines IL-6 and IL-8 in primary cultures established following in vivo LPS challenge or, in response to in vitro LPS treatment. Postnatal ozone exposure resulted in significantly attenuated IL-6 mRNA and protein expression in primary cultures from juvenile animals; IL-8 mRNA was also significantly reduced. The effect of antecedent ozone exposure was modulated by in vivo LPS challenge, as primary cultures exhibited enhanced cytokine expression upon secondary in vitro LPS treatment. Assessment of potential IL-6-targeting microRNAs miR-149, miR-202, and miR-410 showed differential expression in primary cultures based upon animal exposure history. Functional assays revealed that miR-149 is capable of binding to the IL-6 3′ UTR and decreasing IL-6 protein synthesis in airway epithelial cell lines. Cumulatively, our findings suggest that episodic ozone during early life contributes to the molecular programming of airway epithelium, such that memory from prior exposures is retained in the form of a dysregulated IL-6 and IL-8 response to LPS; differentially expressed microRNAs such as miR-149 may play a role in the persistent modulation of the epithelial innate

  17. Interrelation of experimental exposure and ambient air-quality data for comparison of ozone-exposure indices and estimating agricultural losses

    SciTech Connect

    Lee, E.H.; Tingey, D.T.; Hogsett, W.E.

    1989-06-01

    This report evaluates ambient air quality indicators for ozone (O{sub 3}) and estimates the exposure levels associated with agricultural losses. In support of the U.S. EPA Office of Air Quality Planning and Standards review and evaluation of a secondary National Ambient Air Quality Standard for ozone, the Terrestrial Branch within the Corvallis Environmental Research Laboratory investigated alternative exposure indices for characterizing the adverse effects of ozone on agriculture, using experimental data from the National Crop Loss Assessment Network program. Scientific and technical information on ozone and its effects on vegetation, natural ecosystems, natural and artificial materials, and human welfare necessitates a secondary standard that adequately describes the temporal variations of exposure and their effects on plant production and correlates well with short- and long-term exposures. The identification of an appropriate ozone standard that protects against crop-yield losses proceeds along two lines: regression analysis of plant response data against various exposure indices to determine indices that best depict biological response, and ambient air quality analysis of ambient O{sub 3} data to identify indices that correlate well with various exposure patterns.

  18. Characterization of the oxidant generation by inflammatory cells lavaged from rat lungs following acute exposure to ozone

    SciTech Connect

    Esterline, R.L.; Bassett, D.J.; Trush, M.A.

    1989-06-15

    Following exposure to 2 ppm ozone for 4 hr, two distinct effects on rat lung inflammatory cell oxidant generation were observed. TPA- and opsonized zymosan-stimulated superoxide production by the inflammatory cell population was found to be maximally inhibited 24 hr following ozone exposure. In contrast, luminol-amplified chemiluminescence increased 24 hr following ozone exposure, coinciding with an increase in the percentage of neutrophils and myeloperoxidase in the inflammatory cell population. Supporting the involvement of myeloperoxidase in the enhanced oxidant-generating status of these cells, the luminol-amplified chemiluminescence was found to be azide-, but not superoxide dismutase-inhibitable. Additionally, this cell population was found to generate taurine chloramines, a myeloperoxidase-dependent function which was absent prior to the ozone exposure and also demonstrated enhanced activation of benzo(a)pyrene-7,8-dihydrodiol to its light-emitting dioxetane intermediate. Addition of myeloperoxidase to control alveolar macrophages resulted in enhanced luminol-amplified chemiluminescence, taurine chloramine generation, and enhanced chemiluminescence from benzo(a)pyrene-7,8-dihydrodiol demonstrating that, in the presence of myeloperoxidase, alveolar macrophages are capable of supporting myeloperoxidase-dependent reactions. The possibility of such an interaction occurring in vivo is suggested by the detection of myeloperoxidase activity in the cell-free lavagates of ozone-exposed rats. These studies suggest that neutrophils recruited to ozone-exposed lungs alter the oxidant-generating capabilities in the lung which could further contribute to lung injury or to the metabolism of inhaled xenobiotics.

  19. Oxidative stress-dependent changes in immune responses and cell death in the substantia nigra after ozone exposure in rat

    PubMed Central

    Rivas-Arancibia, Selva; Zimbrón, Luis Fernando Hernández; Rodríguez-Martínez, Erika; Maldonado, Perla D.; Borgonio Pérez, Gabino; Sepúlveda-Parada, María

    2015-01-01

    Parkinson's disease has been associated with the selective loss of neurons in the substantia nigra pars compacta. Increasing evidence suggests that oxidative stress plays a major role. The resulting increase in reactive oxygen species triggers a sequence of events that leads to cell damage, activation of microglia cells and neuroinflammatory responses. Our objective was to study whether chronic exposure to low doses of ozone, which produces oxidative stress itself, induces progressive cell death in conjunction with glial alterations in the substantia nigra. Animals were exposed to an ozone-free air stream (control) or to low doses of ozone for 7, 15, 30, 60, or 90 days. Each group underwent (1) spectrophotometric analysis for protein oxidation; (2) western blot testing for microglia reactivity and nuclear factor kappa B expression levels; and (3) immunohistochemistry for cytochrome c, GFAP, Iba-1, NFkB, and COX-2. Our results indicate that ozone induces an increase in protein oxidation levels, changes in activated astrocytes and microglia, and cell death. NFkB and cytochrome c showed an increase until 30 days of exposure, while cyclooxygenase 2 in the substantia nigra increased from 7 days up to 90 days of repetitive ozone exposure. These results suggest that oxidative stress caused by ozone exposure induces changes in inflammatory responses and progressive cell death in the substantia nigra in rats, which could also be occurring in Parkinson's disease. PMID:25999851

  20. Oxidative stress-dependent changes in immune responses and cell death in the substantia nigra after ozone exposure in rat.

    PubMed

    Rivas-Arancibia, Selva; Zimbrón, Luis Fernando Hernández; Rodríguez-Martínez, Erika; Maldonado, Perla D; Borgonio Pérez, Gabino; Sepúlveda-Parada, María

    2015-01-01

    Parkinson's disease has been associated with the selective loss of neurons in the substantia nigra pars compacta. Increasing evidence suggests that oxidative stress plays a major role. The resulting increase in reactive oxygen species triggers a sequence of events that leads to cell damage, activation of microglia cells and neuroinflammatory responses. Our objective was to study whether chronic exposure to low doses of ozone, which produces oxidative stress itself, induces progressive cell death in conjunction with glial alterations in the substantia nigra. Animals were exposed to an ozone-free air stream (control) or to low doses of ozone for 7, 15, 30, 60, or 90 days. Each group underwent (1) spectrophotometric analysis for protein oxidation; (2) western blot testing for microglia reactivity and nuclear factor kappa B expression levels; and (3) immunohistochemistry for cytochrome c, GFAP, Iba-1, NFkB, and COX-2. Our results indicate that ozone induces an increase in protein oxidation levels, changes in activated astrocytes and microglia, and cell death. NFkB and cytochrome c showed an increase until 30 days of exposure, while cyclooxygenase 2 in the substantia nigra increased from 7 days up to 90 days of repetitive ozone exposure. These results suggest that oxidative stress caused by ozone exposure induces changes in inflammatory responses and progressive cell death in the substantia nigra in rats, which could also be occurring in Parkinson's disease. PMID:25999851

  1. Effects of Gaseous Ozone Exposure on Bacterial Counts and Oxidative Properties in Chicken and Duck Breast Meat

    PubMed Central

    Muhlisin, Muhlisin; Utama, Dicky Tri; Lee, Jae Ho; Choi, Ji Hye; Lee, Sung Ki

    2016-01-01

    The effects of gaseous ozone exposure on the bacterial counts and oxidative properties were evaluated in duck and chicken breast fillets, which were stored under a continuous flux of gaseous ozone (10×10−6 kg O3/m3/h) at 4±1℃ for 4 d. The ozone generator was set to on for 15 min and off for 105 min, and this cyclic timer was set during storage. Ozone effectively reduced the growth of coliform, aerobic and anaerobic bacteria in both chicken and duck breast. However, lipid oxidation occurred faster in duck breast than chicken breast with higher degree of discoloration, TBARS value, and antioxidant enzyme (glutathione peroxidase and catalase) activity decline rates. It is concluded that ozone effectively controlled the growth of bacteria in both chicken and duck breast with less effects on oxidative deterioration in chicken breast. PMID:27433112

  2. Effects of Gaseous Ozone Exposure on Bacterial Counts and Oxidative Properties in Chicken and Duck Breast Meat.

    PubMed

    Muhlisin, Muhlisin; Utama, Dicky Tri; Lee, Jae Ho; Choi, Ji Hye; Lee, Sung Ki

    2016-01-01

    The effects of gaseous ozone exposure on the bacterial counts and oxidative properties were evaluated in duck and chicken breast fillets, which were stored under a continuous flux of gaseous ozone (10×10(-6) kg O3/m(3)/h) at 4±1℃ for 4 d. The ozone generator was set to on for 15 min and off for 105 min, and this cyclic timer was set during storage. Ozone effectively reduced the growth of coliform, aerobic and anaerobic bacteria in both chicken and duck breast. However, lipid oxidation occurred faster in duck breast than chicken breast with higher degree of discoloration, TBARS value, and antioxidant enzyme (glutathione peroxidase and catalase) activity decline rates. It is concluded that ozone effectively controlled the growth of bacteria in both chicken and duck breast with less effects on oxidative deterioration in chicken breast. PMID:27433112

  3. The inoculating role of previous exposure to potentially traumatic life events on coping with prolonged exposure to rocket attacks: A lifespan perspective.

    PubMed

    Palgi, Yuval; Gelkopf, Marc; Berger, Rony

    2015-06-30

    Relatively little research have addressed the effect of prolonged exposure to rocket attacks with a lifespan perspective and only a handful of these studies focused on the effect of this exposure as a function of aging. The present study examined the effects of seven years of rocket attacks fired toward the south of Israel on adult participants of different ages. We examined whether potentially traumatic life events (PTLEs) unrelated to rocket attacks moderated the association between post-traumatic stress (PTS) symptoms and age. Data were obtained from a 2007 telephone survey using the Random Digit Dialing method and including 343 individuals (76.7% participation rate). Exposure to rockets, PTLEs, global distress, and post-traumatic symptomatology were assessed. Older age was associated with a higher level of PTS symptoms. Higher PTLE levels attenuated the association between age and PTS symptoms. Our results suggest that age is a risk factor for developing PTS symptoms under prolonged exposure to rocket attacks. However, previous levels of exposure to other negative events, as well as gender, appear to inoculate a person to stress, thus modulating the age-PTS association.

  4. The inoculating role of previous exposure to potentially traumatic life events on coping with prolonged exposure to rocket attacks: A lifespan perspective.

    PubMed

    Palgi, Yuval; Gelkopf, Marc; Berger, Rony

    2015-06-30

    Relatively little research have addressed the effect of prolonged exposure to rocket attacks with a lifespan perspective and only a handful of these studies focused on the effect of this exposure as a function of aging. The present study examined the effects of seven years of rocket attacks fired toward the south of Israel on adult participants of different ages. We examined whether potentially traumatic life events (PTLEs) unrelated to rocket attacks moderated the association between post-traumatic stress (PTS) symptoms and age. Data were obtained from a 2007 telephone survey using the Random Digit Dialing method and including 343 individuals (76.7% participation rate). Exposure to rockets, PTLEs, global distress, and post-traumatic symptomatology were assessed. Older age was associated with a higher level of PTS symptoms. Higher PTLE levels attenuated the association between age and PTS symptoms. Our results suggest that age is a risk factor for developing PTS symptoms under prolonged exposure to rocket attacks. However, previous levels of exposure to other negative events, as well as gender, appear to inoculate a person to stress, thus modulating the age-PTS association. PMID:25863821

  5. Increased CCL24/eotaxin-2 with postnatal ozone exposure in allergen-sensitized infant monkeys is not associated with recruitment of eosinophils to airway mucosa

    SciTech Connect

    Chou, Debbie L.; Gerriets, Joan E.; Schelegle, Edward S.; Hyde, Dallas M.; Miller, Lisa A.

    2011-12-15

    Epidemiology supports a causal link between air pollutant exposure and childhood asthma, but the mechanisms are unknown. We have previously reported that ozone exposure can alter the anatomic distribution of CD25+ lymphocytes in airways of allergen-sensitized infant rhesus monkeys. Here, we hypothesized that ozone may also affect eosinophil trafficking to allergen-sensitized infant airways. To test this hypothesis, we measured blood, lavage, and airway mucosa eosinophils in 3-month old monkeys following cyclical ozone and house dust mite (HDM) aerosol exposures. We also determined if eotaxin family members (CCL11, CCL24, CCL26) are associated with eosinophil location in response to exposures. In lavage, eosinophil numbers increased in animals exposed to ozone and/or HDM. Ozone + HDM animals showed significantly increased CCL24 and CCL26 protein in lavage, but the concentration of CCL11, CCL24, and CCL26 was independent of eosinophil number for all exposure groups. In airway mucosa, eosinophils increased with exposure to HDM alone; comparatively, ozone and ozone + HDM resulted in reduced eosinophils. CCL26 mRNA and immunofluorescence staining increased in airway mucosa of HDM alone animals and correlated with eosinophil volume. In ozone + HDM animal groups, CCL24 mRNA and immunofluorescence increased along with CCR3 mRNA, but did not correlate with airway mucosa eosinophils. Cumulatively, our data indicate that ozone exposure results in a profile of airway eosinophil migration that is distinct from HDM mediated pathways. CCL24 was found to be induced only by combined ozone and HDM exposure, however expression was not associated with the presence of eosinophils within the airway mucosa. -- Highlights: Black-Right-Pointing-Pointer Ozone can modulate the localization of eosinophils in infant allergic airways. Black-Right-Pointing-Pointer Expression of eotaxins within the lung is affected by ozone and allergen exposure. Black-Right-Pointing-Pointer CCL24 induction by

  6. Effects of ozone exposure: a comparison between oral and nasal breathing

    SciTech Connect

    Hynes, B.; Silverman, F.; Cole, P.; Corey, P.

    1988-09-01

    Mode of inhalation, by nose or by mouth, as a determinant of pulmonary toxicity to acute inhalant exposure has been investigated incompletely. This communication addresses whether there are significant differences in toxic pulmonary responses to acute ozone (O/sub 3/) exposure between differing modes of inhalation (nasal vs. oral breathing). Changes in the results of pulmonary function tests and symptomatology of healthy young adults were compared following both exclusive nose and exclusive mouth breathing during a 30-min exposure to approximately 0.4 ppm O/sub 3/ under conditions of moderate continuous exercise. In this single-blind, randomized, crossover study, no significant differences in either the results of pulmonary function tests or in symptomatology were found between the two modes of inhalation.

  7. Increased lung resistance after diesel particulate and ozone co-exposure not associated with enhanced lung inflammation in allergic mice*

    EPA Science Inventory

    Exposure to diesel exhaust particle matter (DEP) exacerbates asthma. Likewise, similar effects have been reported with exposure to the oxidizing air pollutant ozone (03) . Since levels of both pollutants in ambient air tend to be simultaneously elevated, we investigated the possi...

  8. The Variable Effects of Ozone and/or Diesel Particulate Inhalation Exposure on Allergic Airways Responses in Mice

    EPA Science Inventory

    Exposure to diesel exhaust particle matter (DEP) associated with the combustion of diesel fuel exacerbates asthma. Likewise, similar effects have been reported with exposure to the oxidizing air pollutant ozone (O3). Since levels of both pollutants in ambient air are e...

  9. Effect of maternal exposure to ozone on reproductive outcome and immune, inflammatory, and allergic responses in the offspring

    EPA Science Inventory

    There is growing concern that exposure to air pollutants during pregnancy affects health outcomes in the offspring due to alterations in the development of immune and other homeostatic processes. To assess the risks of maternal inhalation exposure to ozone (O3), timed pregnant BA...

  10. Effects of herbicides on Lemna gibba and recovery from damage after prolonged exposure.

    PubMed

    Mohammad, M; Itoh, K; Suyama, K

    2010-04-01

    To determine the potential impact of contaminants on the aquatic vascular plants Lemna sp., toxicity tests are usually conducted for a 4- to 14-day exposure, and the toxicity is usually expressed as EC50. However, the effects of longer exposure and the recovery potential after exposure to chemicals are other important factors which should be considered. We present the relative risks of a variety of exposure scenarios and recovery potentials from damage, using herbicides with different modes of action. Toxicity was assessed on the basis of both EC50 and relative growth rate (RGR) compared with untreated controls in exposure and recovery. The EC50 of atrazine was found to be 89 ppb, and its phytostatic concentrations were 1600 and 800 ppb for exposure periods of 14 and 28 days, respectively, and no phytocidal effects were observed up to 3200 ppb for a 28-day exposure. The RGR in recovery was not affected by the RGR in exposure, and regrowth was possible even after complete inhibition of growth for 28 days at the highest concentration tested. Alachlor, with an EC50 of 31 ppb, was phytostatic at 400 ppb for a 14-day exposure and phytocidal at 200 ppb for 21- and 28-day exposures. Paraquat, with an EC50 of 31 ppb, showed phytocidal rather than phytostatic effects. All phytostatic fronds could not grow in the recovery period, and the phytocidal concentration decreased with exposure period, from 80 ppb for a 7-day exposure to 20 ppb for 21- and 28-day exposures. The RGR of alachlor and paraquat in recovery was dependent on the RGR in exposure. In the case of cyclosulfamuron, phytostatic concentrations were 100 and 50 ppb for 7- and 14-day exposures, respectively. In the case of exposures longer than 21 days, however, it exhibited phytocidal activity at 10 ppb. The results of this study suggest that it is important to examine the effects of chemicals over a longer exposure period as well as the recovery potential from damage for reliable ecological risk assessment. PMID

  11. Projecting Future Changes in Seasonal Vegetative Exposure to Ozone in the Western US Using GEOS-Chem Adjoint

    NASA Astrophysics Data System (ADS)

    Lapina, K.; Henze, D. K.; Milford, J. B.

    2014-12-01

    Frequent exposure to elevated levels of ozone leads to negative impacts on ecosystems including the loss of ozone-sensitive tree species and agricultural crops in many regions of the United States. Information on emission sources contributing to these losses is crucial for developing a successful strategy to mitigate the negative effects of ozone on vegetation. A cumulative ozone exposure metric, W126, has been considered by the US EPA for use as secondary ozone standard. The rural West of the US has been demonstrated to have an especially great potential for disconnect between attaining primary versus W126-based ozone standards. In this work we separate the relative impact of emissions sources for the W126 in the Western US using forward and adjoint simulations with the global chemical transport model GEOS-Chem. The obtained source contributions are separated by different locations, species, and sectors and are combined with representative concentration pathway (RCP) anthropogenic emission scenarios to project future changes in W126 through 2050. Focusing on the foreign influences we find that the change in Chinese emissions alone is projected to lead to up to 20% increase in the W126 levels in the West and is strongly dependent on the RCP scenario. We further use concentration-response functions based on the W126 index to estimate the loss of four ozone-sensitive species in the West - ponderosa pine, Douglas Fir, red alder and quacking aspen.

  12. Consequences of prolonged inhalation of ozone on f344/n rats: Collaborative studies. Part 3. Effects on complex carbohydrates of lung connective tissue. Research report, April 1991-January 1994

    SciTech Connect

    Radhakrishnamurthy, B.

    1994-09-01

    Glycosaminoglycans are constituents of proteoglycans, which are integral components of lung connective tissue. Changes in the metabolism of glycosaminoglycans have been noted in pulmonary fibrosis and emphysema. The authors studied quantitative and qualitative changes of glycosaminoglycans in the lungs of rats exposed to a range of ozone levels (0, 0.12, 0.5, or 1.0 parts per million) for 20 months. Although wide variations in total glycosaminoglycans concentrations exist among individual animals within each exposure group, regression analyses of data indicated a monotonic and statistically significant decrease of total glycosaminoglycans after ozone exposure. Among individual glycosaminoglycans, hyaluronan, chondroitin 4-sulfate, and chondroitin 6-sulfate levels decreased significantly in animals exposed to ozone when compared with control animals. Heparan sulfate concentration exhibited a significant trend toward increase with increasing doses of ozone, but the difference in heparan sulfate concentration animals exposed to ozone and control animals was not significant. Gel filtration studies of glycosaminoglycans in pooled sampled indicated that the molecular size of hyaluronan in animals exposed to ozone was lower than it was in control animals. The authors noted differences in heparan sulfate`s chemical properties and its affinity to antithrombin III between animals exposed to ozone and control animals. These observations indicate that inhalation of ozone for 20 months affects normal cellular metabolism of proteoglycans, which may contribute to the functional impairment of the lung.

  13. Low-Temperature Ozone Exposure Technique to Modulate the Stoichiometry of WO(x) Nanorods and Optimize the Electrochromic Performance

    SciTech Connect

    Lin, F.; Li, C. P.; Chen, G.; Tenent, R. C.; Wolden, C. A.; Gillaspie, D. T.; Dillon, A. C.; Richards, R. M.; Engtrakul, C.

    2012-06-29

    A low-temperature ozone exposure technique was employed for the post-treatment of WO{sub x} nanorod thin films fabricated from hot-wire chemical vapor deposition (HWCVD) and ultrasonic spray deposition (USD) techniques. The resulting films were characterized with x-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, UV-vis-NIR spectroscopy and x-ray photoelectron spectroscopy (XPS). The stoichiometry and surface crystallinity of the WO{sub x} thin films were subsequently modulated upon ozone exposure and thermal annealing without particle growth. The electrochromic performance was studied in a LiClO{sub 4}-propylene carbonate electrolyte, and the results suggest that the low-temperature ozone exposure technique is superior to the traditional high-temperature thermal annealing (employed to more fully oxidize the WO{sub x}). The optical modulation at 670 nm was improved from 35% for the as-deposited film to 57% for the film after ozone exposure at 150 C. The coloration efficiency was improved and the switching speed to the darkened state was significantly accelerated from 18.0 s for the as-deposited film to 11.8 s for the film after the ozone exposure. The process opens an avenue for low-temperature and cost-effective manufacturing of electrochromic films, especially on flexible polymer substrates.

  14. Dose-dependent tolerance to ozone. I. Tracheobronchial epithelial reorganization in rats after 20 months' exposure.

    PubMed Central

    Plopper, C. G.; Chu, F. P.; Haselton, C. J.; Peake, J.; Wu, J.; Pinkerton, K. E.

    1994-01-01

    Two salient features of the pulmonary response to reactive oxidant air pollutants such as ozone are the heterogeneity of response by site within the respiratory tract and the development of tolerance to injury with repeated exposure. The purpose of this study was to establish whether the development of tolerance to long-term exposure is associated with changes in the tracheobronchial epithelium. Male F344-N rats were exposed to 0, 0.12, 0.5, or 1.0 ppm ozone 6 hours/day for 5 days/week for 20 months and killed 1 week post-exposure. Samples for light microscopic morphometry were obtained by microdissection from each infusion-fixed trachea and left lung lobe and included: 1) a cranial bronchus with short path length (generation no. 4 to 5) and small diameter; 2) a central bronchus with short path length (generation no. 4 to 5) and large diameter; and 3) a caudal bronchus with long path length (generation no. 10 to 12) and small diameter. In addition, three sites within the central acinus were examined from cranial, central, and caudal regions. These sites included terminal bronchiole, 0.5 to 1 mm proximal to terminal bronchiole and bronchiolarized alveolar duct. Intraepithelial mucin storage (AB/PAS-positive material quantified by image analysis) within the trachea decreased with dose. Mucin storage was unchanged in the central bronchus, increased threefold with dose in the caudal bronchus, and was six times higher in the cranial bronchus at 1.0 ppm ozone. Epithelial composition was unchanged in trachea or any bronchi; however, we noted a significant dose-dependent increase in nonciliated cell mass and volume fraction in terminal bronchioles in all three regions. There was also a significant increase in nonciliated cell mass in the bronchiolarized alveolar ducts. Bronchiolar nonciliated cells were identified greater than fourfold further into alveolar ducts in 1.0 ppm exposed than in 0 ppm animals. Nonciliated cells occurred almost 200 microns deeper into alveolar

  15. An outbreak of illness after occupational exposure to ozone and acid chlorides.

    PubMed Central

    Ng, T P; Tsin, T W; O'Kelly, F J

    1985-01-01

    New labelling processes installed without adequate ventilation control in an electric motor factory exposed production line workers to toxic gases. Symptoms of eye and respiratory tract irritation together with complaints of headache, fever, chills, dizziness, malaise, general weakness, nausea, and vomiting were widespread. Chest signs, radiographic abnormalities, reduction in ventilatory function, and blood gas abnormalities were found in some cases. Epidemiological analysis of the spatial and temporal distribution of cases supported an exposure effect relationship. Investigations suggested ozone and possibly phosgene and associated trichloroacetyl chlorides as the toxic agents that were generated by an ultraviolet print curing arrangement and perchloroethylene used as a cleaning solvent. PMID:4041387

  16. Effect of ozone exposure and infection on bronchoalveolar lavage: Sex differences in response patterns.

    PubMed Central

    Gan, Xiaozhuang; Umstead, Todd M.; Haque, Rizwanul; Wang, Guirong; Floros, Joanna

    2014-01-01

    Female mice exhibit a better survival rate than males after infection, but if infection follows an ozone-induced oxidative stress, male survival exceeds that of females. Our goal was to study bronchoalveolar lavage factors that contribute to these sex differences in outcome. We studied parameters at 4, 24, and 48 hours after ozone exposure and infection, including markers of inflammation, oxidative stress, and tissue damage, and surfactant phospholipids and surfactant protein A (SP-A). A multianalyte immunoassay at the 4 hr time point measured 59 different cytokines, chemokines, and other proteins. We found that: 1) Although some parameters studied revealed sex differences, no sex differences were observed in LDH, total protein, MIP-2, and SP-A. Males showed more intragroup significant differences in SP-A between filtered air- and ozone-exposed mice compared to females. 2) Oxidized dimeric SP-A was higher in FA-exposed female mice. 3) Surfactant phospholipids were typically higher in males. 4) The multianalyte data revealed differences in the exuberance of responses under different conditions - males in response to infection and females in response to oxidative stress. These more exuberant, and presumably less well-controlled responses associate with the poorer survival. We postulate that the collective effects of these sex differences in response patterns of lung immune cells may contribute to the clinical outcomes previously observed. PMID:24769259

  17. Interaction of drought and ozone exposure on isoprene emission from extensively cultivated poplar.

    PubMed

    Yuan, Xiangyang; Calatayud, Vicent; Gao, Feng; Fares, Silvano; Paoletti, Elena; Tian, Yuan; Feng, Zhaozhong

    2016-10-01

    The combined effects of ozone (O3 ) and drought on isoprene emission were studied for the first time. Young hybrid poplars (clone 546, Populus deltoides cv. 55/56 x P. deltoides cv. Imperial) were exposed to O3 (charcoal-filtered air, CF, and non-filtered air +40 ppb, E-O3 ) and soil water stress (well-watered, WW, and mild drought, MD, one-third irrigation) for 96 days. Consistent with light-saturated photosynthesis (Asat ), intercellular CO2 concentration (Ci ) and chlorophyll content, isoprene emission depended on drought, O3 , leaf position and sampling time. Drought stimulated emission (+38.4%), and O3 decreased it (-40.4%). Ozone increased the carbon cost per unit of isoprene emission. Ozone and drought effects were stronger in middle leaves (13th-15th from the apex) than in upper leaves (6th-8th). Only Asat showed a significant interaction between O3 and drought. When the responses were up-scaled to the entire-plant level, however, drought effects on total leaf area translated into around twice higher emission from WW plants in clean air than in E-O3 . Our results suggest that direct effects on plant emission rates and changes in total leaf area may affect isoprene emission from intensively cultivated hybrid poplar under combined MD and O3 exposure, with important feedbacks for air quality.

  18. Interaction of drought and ozone exposure on isoprene emission from extensively cultivated poplar.

    PubMed

    Yuan, Xiangyang; Calatayud, Vicent; Gao, Feng; Fares, Silvano; Paoletti, Elena; Tian, Yuan; Feng, Zhaozhong

    2016-10-01

    The combined effects of ozone (O3 ) and drought on isoprene emission were studied for the first time. Young hybrid poplars (clone 546, Populus deltoides cv. 55/56 x P. deltoides cv. Imperial) were exposed to O3 (charcoal-filtered air, CF, and non-filtered air +40 ppb, E-O3 ) and soil water stress (well-watered, WW, and mild drought, MD, one-third irrigation) for 96 days. Consistent with light-saturated photosynthesis (Asat ), intercellular CO2 concentration (Ci ) and chlorophyll content, isoprene emission depended on drought, O3 , leaf position and sampling time. Drought stimulated emission (+38.4%), and O3 decreased it (-40.4%). Ozone increased the carbon cost per unit of isoprene emission. Ozone and drought effects were stronger in middle leaves (13th-15th from the apex) than in upper leaves (6th-8th). Only Asat showed a significant interaction between O3 and drought. When the responses were up-scaled to the entire-plant level, however, drought effects on total leaf area translated into around twice higher emission from WW plants in clean air than in E-O3 . Our results suggest that direct effects on plant emission rates and changes in total leaf area may affect isoprene emission from intensively cultivated hybrid poplar under combined MD and O3 exposure, with important feedbacks for air quality. PMID:27411672

  19. Enhanced inflammatory response to acute ozone exposure in rats during pregnancy and lactation

    SciTech Connect

    Gunnison, A.F.; Weideman, P.A.; Sobo, M. )

    1992-11-01

    Experimental evidence from several studies suggests that pregnant animals and women are more susceptible to oxidants than nonpregnant controls. In the study reported here, we sought to determine whether pregnant rats are more sensitive than age-matched virgin females to the inflammatory effects of ozone, a gaseous oxidant of considerable environmental significance. Rats at several stages of pregnancy and lactation, as well as age-matched virgin females, were exposed to 1 ppm ozone for 6 hr. Controls were sham-exposed to pure air for an identical period of time. Bronchoalveolar lavage was performed 24 hr after the beginning of exposure, and components of the lavage fluid considered to be indicators of inflammation were used to assess the severity of pulmonary inflammation. The results of this experiment showed that significantly enhanced sensitivity to ozone-induced pulmonary inflammation develops during pregnancy, is maintained during lactation, and disappears following lactation. Implicit in this pattern of differential sensitivity in rats is the possibility of a similar pattern of inflammatory response in analogous groups of humans as well as the potential for applicability to other oxidative pollutants.

  20. Nasal epithelial and inflammatory response to ozone exposure: a review of laboratory-based studies published since 1985.

    PubMed

    Nikasinovic, L; Momas, I; Seta, N

    2003-01-01

    This article summarizes biological events in human and animal nasal epithelium after short- and long-term exposure to ozone, the principal agent in photochemical smog. Despite anatomical and histological interspecies differences, ozone exposures resulted in common nasal qualitative alterations with an anterior-posterior gradient of phenomena occurring immediately, and with a lag time postexposure: epithelial disruption and increased permeability, inflammatory cell influx, and proliferative and secretory responses. Described mechanisms of toxicity included a direct effect of ozone on epithelial lining fluid and cellular membranes and the subsequent release of cytokines and cyclooxygenase and lipoxygenase products. An indirect effect of ozone was indicated by a decreased mucociliary clearance, free radicals production interacting with a gene promoting factor, and increased DNA synthesis. Studies highlighted the pivotal role of activated neutrophils and mast cells leading to the release of deleterious enzymes (tryptase, eosinophil cationic protein) and numerous cytokines. Experiments performed with ozone exposure/allergen challenge reported that, besides the intrinsic deleterious properties of ozone, it also had a priming effect on the late-phase response to allergen challenge, providing new insights into the pathophysiology of respiratory allergic diseases. PMID:12888446

  1. BVOC responses to realistic nitrogen fertilization and ozone exposure in silver birch.

    PubMed

    Carriero, G; Brunetti, C; Fares, S; Hayes, F; Hoshika, Y; Mills, G; Tattini, M; Paoletti, E

    2016-06-01

    Emission of BVOC (Biogenic Volatile Organic Compounds) from plant leaves in response to ozone exposure (O3) and nitrogen (N) fertilization is poorly understood. For the first time, BVOC emissions were explored in a forest tree species (silver birch, Betula pendula) exposed for two years to realistic levels of O3 (35, 48 and 69 ppb as daylight average) and N (10, 30 and 70 kg ha(-1) yr(-1), applied weekly to the soil as ammonium nitrate). The main BVOCs emitted were: α-pinene, β-pinene, limonene, ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and hexanal. Ozone exposure increased BVOC emission and reduced total leaf area. The effect on emission was stronger when a short-term O3 metric (concentrations at the time of sampling) rather than a long-term one (AOT40) was used. The effect of O3 on total leaf area was not able to compensate for the stimulation of emission, so that responses to O3 at leaf and whole-plant level were similar. Nitrogen fertilization increased total leaf area, decreased α-pinene and β-pinene emission, and increased ocimene, hexanal and DMNT emission. The increase of leaf area changed the significance of the emission response to N fertilization for most compounds. Nitrogen fertilization mitigated the effects of O3 exposure on total leaf area, while the combined effects of O3 exposure and N fertilization on BVOC emission were additive and not synergistic. In conclusion, O3 exposure and N fertilization have the potential to affect global BVOC via direct effects on plant emission rates and changes in leaf area. PMID:26809503

  2. BVOC responses to realistic nitrogen fertilization and ozone exposure in silver birch.

    PubMed

    Carriero, G; Brunetti, C; Fares, S; Hayes, F; Hoshika, Y; Mills, G; Tattini, M; Paoletti, E

    2016-06-01

    Emission of BVOC (Biogenic Volatile Organic Compounds) from plant leaves in response to ozone exposure (O3) and nitrogen (N) fertilization is poorly understood. For the first time, BVOC emissions were explored in a forest tree species (silver birch, Betula pendula) exposed for two years to realistic levels of O3 (35, 48 and 69 ppb as daylight average) and N (10, 30 and 70 kg ha(-1) yr(-1), applied weekly to the soil as ammonium nitrate). The main BVOCs emitted were: α-pinene, β-pinene, limonene, ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and hexanal. Ozone exposure increased BVOC emission and reduced total leaf area. The effect on emission was stronger when a short-term O3 metric (concentrations at the time of sampling) rather than a long-term one (AOT40) was used. The effect of O3 on total leaf area was not able to compensate for the stimulation of emission, so that responses to O3 at leaf and whole-plant level were similar. Nitrogen fertilization increased total leaf area, decreased α-pinene and β-pinene emission, and increased ocimene, hexanal and DMNT emission. The increase of leaf area changed the significance of the emission response to N fertilization for most compounds. Nitrogen fertilization mitigated the effects of O3 exposure on total leaf area, while the combined effects of O3 exposure and N fertilization on BVOC emission were additive and not synergistic. In conclusion, O3 exposure and N fertilization have the potential to affect global BVOC via direct effects on plant emission rates and changes in leaf area.

  3. Respiratory responses of vigorously exercising children to 0. 12 ppm ozone exposure

    SciTech Connect

    McDonnell, W.F. 3d.; Chapman, R.S.; Leigh, M.W.; Strope, G.L.; Collier, A.M.

    1985-10-01

    Changes in respiratory function have been suggested for children exposed to less than 0.12 ppm ozone (O3) while engaged in normal activities. Because the results of these studies have been confounded by other variables, such as temperature or the presence of other pollutants or have been questioned as to the adequacy of exposure measurements, the authors determined the acute response of children exposed to 0.12 ppm O3 in a controlled chamber environment. Twenty-three white males 8 to 11 yr of age were exposed once to clean air and once to 0.12 ppm O3 in random order. Exposures were for 2.5 h and included 2 h of intermittent heavy exercise. Measures of forced expiratory volume in one second (FEV1) and the symptom cough were determined prior to and after each exposure. A significant decline in FEV1 was found after the O3 exposure compared to the air exposure, and it appeared to persist for 16 to 20 h. No significant increase in cough was found due to O3 exposure. Forced vital capacity, specific airways resistance, respiratory frequency, tidal volume, and other symptoms were measured in a secondary exploratory analysis of this study.

  4. The effect of prolonged exposure to 750{degree}C air on the tribological performance of PM212

    SciTech Connect

    Bemis, K.; Bogdanski, M.S.; DellaCorte, C.; Sliney, H.E.

    1994-05-01

    The effect of prolonged exposure to 750C air on tribological performance and dimensional stability of PM212, a high temperature, self-lubricating composite, is studied. PM212, contains 70% metal-bonded Cr{sub 3}C{sub 2}, 15% BaF{sub 2}/CaF{sub 2} eutectic and 15% silver. Rub blocks were fabricated from PM212 by cold isostatic pressing followed by sintering. Prior to tribo-testing, the rub blocks were exposed to 750C air from 100 to 1000 hours. Then, the rub blocks were slid against nickel-based superalloy disks in a double-rub-block tribometer in air under 66N load at temperatures from 25 to 750C with a sliding velocity of 0.36 m/s. Unexposed rub blocks were tested for baseline comparison. Friction coefficients ranged from 0.24 to 0.37 for unexposed rub blocks and from 0.32 to 0.56 for the exposed ones. Wear for both the composite blocks and superalloy disks was typically in the moderate to low range of 10{sup {minus}5} to 10{sup {minus}6} mm{sup 3} /N-m. Friction and wear data were similar for the rub blocks exposed for 100, 500, and 1000 hours. Prolonged exposure to 750C air increased friction and wear of the PM212 rub blocks at room temperature, but triboperformance remained unaffected at higher temperatures, probably due to formation of lubricous metal oxides. Dimensional stability of the composite was studied by exposing specimens of varying thicknesses for 500 hours in air at 750C. Block thicknesses were found to increase with increased exposure time until steady state was reached after 100 hours of exposure, probably due to oxidation.

  5. Prolonged Morphine Exposure Induces Increased Firm Adhesion in an in Vitro Model of the Blood–Brain Barrier

    PubMed Central

    Strazza, Marianne; Pirrone, Vanessa; Wigdahl, Brian; Dampier, Will; Lin, Wei; Feng, Rui; Maubert, Monique E.; Weksler, Babette; Romero, Ignacio A.; Couraud, Pierre-Olivier; Nonnemacher, Michael R.

    2016-01-01

    The blood–brain barrier (BBB) has been defined as a critically important protective barrier that is involved in providing essential biologic, physiologic, and immunologic separation between the central nervous system (CNS) and the periphery. Insults to the BBB can cause overall barrier damage or deregulation of the careful homeostasis maintained between the periphery and the CNS. These insults can, therefore, yield numerous phenotypes including increased overall permeability, interendothelial gap formation, alterations in cytokine and chemokine secretion, and accelerated cellular passage. The current studies expose the human brain microvascular endothelial cell line, hCMEC/D3, to prolonged morphine exposure and aim to uncover the mechanisms underlying alterations in barrier function in vitro. These studies show alterations in the mRNA and protein levels of the cellular adhesion molecules (CAMs) intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and activated leukocyte cell adhesion molecule that correlate with an increased firm adhesion of the CD3+ subpopulation of peripheral blood mononuclear cells (PBMCs). Overall, these studies suggest that prolonged morphine exposure may result in increased cell migration into the CNS, which may accelerate pathological processes in many diseases that involve the BBB. PMID:27294916

  6. Effects of processing and prolonged high temperature exposure on the microstructure of Nb-1Zr-C sheet

    NASA Technical Reports Server (NTRS)

    Uz, Mehmet; Titran, R. H.

    1993-01-01

    High temperature stability of the microstructure of Nb-1Zr sheet containing 0.1 and 0.06 wt. percent C was studied as affected by processing and prolonged 1350 K exposure with and without applied stress. Sheets were fabricated by cold rolling bars that were single-, double-, or triple-extruded at 1900 K. Creep samples were double-annealed (1 h at 1755 K + 2 h at 1475 K) prior to testing at 1350 K and 10,000 - 34,500 h. The microstructures of the as-cast, extruded, rolled, DA, and crept samples were characterized using various metallographic and analytical methods. The precipitates were rather coarse Nb2C initially, but transformed to finer (less than or equal to 1 micron) carbides of (Zr, Nb)C with each subsequent high temperature process. The grain size, and the relative amount and morphology of (Zr, Nb)C were found to be affected by the number of extrusions and to some extent by C-content. However, the microstructures of all the crept samples were similar with (Zr, Nb)C distributed throughout the matrix indicating that prolonged exposure to 1350 K gave rise to complete transformation of Nb2C to (Zr, Nb)C regardless of the processing history. These and other observations are presented with the emphasis on the correlation between processing, microstructure, and creep properties.

  7. The effects of ozone exposure and associated injury mechanisms on the central nervous system.

    PubMed

    Martínez-Lazcano, Juan Carlos; González-Guevara, Edith; del Carmen Rubio, María; Franco-Pérez, Javier; Custodio, Verónica; Hernández-Cerón, Miguel; Livera, Carlos; Paz, Carlos

    2013-01-01

    Ozone (O3) is a component of photochemical smog, which is a major air pollutant and demonstrates properties that are harmful to health because of the toxic properties that are inherent to its powerful oxidizing capabilities. Environmental O3 exposure is associated with many symptoms related to respiratory disorders, which include loss of lung function, exacerbation of asthma, airway damage, and lung inflammation. The effects of O3 are not restricted to the respiratory system or function - adverse effects within the central nervous system (CNS) such as decreased cognitive response, decrease in motor activity, headaches, disturbances in the sleep-wake cycle, neuronal dysfunctions, cell degeneration, and neurochemical alterations have also been described; furthermore, it has also been proposed that O3 could have epigenetic effects. O3 exposure induces the reactive chemical species in the lungs, but the short half-life of these chemical species has led some authors to attribute the injurious mechanisms observed within the lungs to inflammatory processes. However, the damage to the CNS induced by O3 exposure is not well understood. In this review, the basic mechanisms of inflammation and activation of the immune system by O3 exposure are described and the potential mechanisms of damage, which include neuroinflammation and oxidative stress, and the signs and symptoms of disturbances within the CNS caused by environmental O3 exposure are discussed. PMID:23585211

  8. Premature mortality in India due to PM2.5 and ozone exposure

    NASA Astrophysics Data System (ADS)

    Ghude, Sachin D.; Chate, D. M.; Jena, C.; Beig, G.; Kumar, R.; Barth, M. C.; Pfister, G. G.; Fadnavis, S.; Pithani, Prakash

    2016-05-01

    This bottom-up modeling study, supported by new population census 2011 data, simulates ozone (O3) and fine particulate matter (PM2.5) exposure on local to regional scales. It quantifies, present-day premature mortalities associated with the exposure to near-surface PM2.5 and O3 concentrations in India using a regional chemistry model. We estimate that PM2.5 exposure leads to about 570,000 (CI95: 320,000-730,000) premature mortalities in 2011. On a national scale, our estimate of mortality by chronic obstructive pulmonary disease (COPD) due to O3 exposure is about 12,000 people. The Indo-Gangetic region accounts for a large part (~42%) of the estimated mortalities. The associated lost life expectancy is calculated as 3.4 ± 1.1 years for all of India with highest values found for Delhi (6.3 ± 2.2 years). The economic cost of estimated premature mortalities associated with PM2.5 and O3 exposure is about 640 (350-800) billion USD in 2011, which is a factor of 10 higher than total expenditure on health by public and private expenditure.

  9. Modulation of human alveolar macrophage properties by ozone exposure in vitro

    SciTech Connect

    Becker, S.; Madden, M.C.; Newman, S.L.; Devlin, R.B.; Koren, H.S.

    1991-01-01

    The study investigated changes in human alveolar macrophage (HAM) function after exposure in vitro to ozone (O3)(0.1-1.0 ppm for 2-4 hr). The functions studied reflect concern that O3 is detrimental to host defense mechanisms in the bronchoalveolar spaces. Exposure of HAM to O3 caused a concentration-dependent increase in release of prostaglandin E2(PGE2), an important modulator of inflammation, phagocytosis, and oxidative burst. Although phagocytosis of particulate immune complexes was decreased by O3, the authors found no change in the quantity of Fc receptors and complement receptors on the HAM surface. Superoxide (O2) production in response to phorbol ester was reduced after exposure of HAM to O3 while the basal O2 release in response to plastic adherence was not affected. Growth inhibition of the opportunistic yeast Cryptococcus neoformans by HAM was not affected by O3 exposure. The production of inflammatory mediators and immune modulators such as tumor necrosis factor-alpha, interleukin 1, and interleukin 6 were not induced by exposure to O3. However, compared to controls, O3-exposed HAM produced significantly lower levels of these cytokines when simulated with bacterial lipopolysaccharide (LPS).

  10. Effect of acute exposure to ozone on heart rate and blood pressure of the conscious rat

    SciTech Connect

    Uchiyama, I.; Simomura, Y.; Yokoyama, E.

    1985-12-01

    Electrocardiogram and arterial blood pressure in conscious and unrestrained rats of various ages were recorded during a 3-hr exposure to filtered air or 1 ppm ozone (O/sub 3/). In general, heart rate and mean arterial blood pressure of rats significantly decreased during exposure to O/sub 3/, whereas these functional parameters remained almost stable during exposure to filtered air. Heart rate usually reached a plateau during the exposure to O/sub 3/. Additionally, PR interval and QRS complex significantly increased and premature atrial contraction and incomplete A-V block were frequently observed during the exposure to O/sub 3/. These circulatory effects of O/sub 3/ were more markedly manifested by rats 11 weeks old than either those 8 or 4 weeks old. On the other hand, no significant difference in the circulatory responses was observed between male and female rats. These circulatory effects of O/sub 3/ may be significant from the viewpoint of health effects, although its mechanisms remain unsolved.

  11. Prolonged exposure to acetaminophen reduces testosterone production by the human fetal testis in a xenograft model.

    PubMed

    van den Driesche, Sander; Macdonald, Joni; Anderson, Richard A; Johnston, Zoe C; Chetty, Tarini; Smith, Lee B; McKinnell, Chris; Dean, Afshan; Homer, Natalie Z; Jorgensen, Anne; Camacho-Moll, Maria E; Sharpe, Richard M; Mitchell, Rod T

    2015-05-20

    Most common male reproductive disorders are linked to lower testosterone exposure in fetal life, although the factors responsible for suppressing fetal testosterone remain largely unknown. Protracted use of acetaminophen during pregnancy is associated with increased risk of cryptorchidism in sons, but effects on fetal testosterone production have not been demonstrated. We used a validated xenograft model to expose human fetal testes to clinically relevant doses and regimens of acetaminophen. Exposure to a therapeutic dose of acetaminophen for 7 days significantly reduced plasma testosterone (45% reduction; P = 0.025) and seminal vesicle weight (a biomarker of androgen exposure; 18% reduction; P = 0.005) in castrate host mice bearing human fetal testis xenografts, whereas acetaminophen exposure for just 1 day did not alter either parameter. Plasma acetaminophen concentrations (at 1 hour after the final dose) in exposed host mice were substantially below those reported in humans after a therapeutic oral dose. Subsequent in utero exposure studies in rats indicated that the acetaminophen-induced reduction in testosterone likely results from reduced expression of key steroidogenic enzymes (Cyp11a1, Cyp17a1). Our results suggest that protracted use of acetaminophen (1 week) may suppress fetal testosterone production, which could have adverse consequences. Further studies are required to establish the dose-response and treatment-duration relationships to delineate the maximum dose and treatment period without this adverse effect.

  12. Physiological responses of mules on prolonged exposure to high altitude (3 650 m)

    NASA Astrophysics Data System (ADS)

    Riar, S. S.; Shankar Bhat, K.; Sen Gupta, J.

    1982-06-01

    Eight healthy male animals were inducted and kept for 2 1/2 years at 3 650 m altitude and subjected to normal work schedules. Physiological measurements viz. heart rate, blood pressure, minute ventilation, oxygen consumption, respiration rate, hemoglobin, packed cell haematocrit volume and eosinophil count were made on these animals at periodic intervals. On acute induction to an altitude of 3 650 m these animals demonstrated a sudden increase in tidal volume, a decrease in Rf and no change in VE, suggesting a decreased dead space/tidal volume ratio at altitude. However, all these changes stabilised within 3 weeks but on prolongation of stay, the physical state of these animals was adversely affected. The respiratory adjustments occurring on return to sea level appear to be a response to thermal stress. The initial increase in heart rate and blood pressure stabilised by the 2nd week.

  13. Prolonged Radiant Exposure of the Middle Ear during Transcanal Endoscopic Ear Surgery.

    PubMed

    Shah, Parth V; Kozin, Elliott D; Remenschneider, Aaron K; Dedmon, Matthew M; Nakajima, Hideko Heidi; Cohen, Michael S; Lee, Daniel J

    2015-07-01

    Transcanal endoscopic ear surgery (EES) provides a high-resolution, wide-field view of the middle ear compared with the conventional operating microscope, reducing the need for a postauricular incision or mastoidectomy. Our group has shown in cadaveric human temporal bone studies that radiant energy from the endoscope tip can quickly elevate temperatures of the tympanic cavity. Elevated temperatures of the middle ear are associated with acute auditory brainstem response shifts in animal models. In EES, proposed methods to decrease middle ear temperature include frequent removal of the endoscope and the use of suction to rapidly dissipate heat; however, the routine application of such cooling techniques remains unknown. Herein, we aim to quantify the duration that the tympanic cavity is typically exposed to the endoscope during routine endoscopic middle ear surgery. We find that the tympanic cavity is exposed to the endoscope without a cooling mechanism for a prolonged period of time.

  14. Exposure of pink salmon embryos to dissolved polynuclear aromatic hydrocarbons delays development, prolonging vulnerability to mechanical damage.

    PubMed

    Carls, Mark G; Thedinga, John F

    2010-06-01

    Exposure to dissolved polynuclear aromatic hydrocarbons (PAHs) from crude oil delays pink salmon (Oncorhynchus gorbuscha) embryo development, thus prolonging their susceptibility to mechanical damage (shock). Exposure also caused mortality, edema, and anemia consistent with previous studies. Hatching and yolk consumption were delayed, indicating the rate of embryonic development was slowed by PAH exposure. The net result was that exposed embryos were more susceptible to shock than normal, unexposed embryos. Susceptibility to shock was protracted by 4-6d for more than a month in embryos exposed to exponentially declining, dissolved PAH concentrations in water passed through oiled rock; the initial total PAH concentration was 22.4microgL(-1) and the geometric mean concentration was 4.5microgL(-1) over the first 20d. Protracted susceptibility to shock caused by exposure to PAHs dissolved from oil could potentially increase the reported incidence of mortality in oiled stream systems, such as those in Prince William Sound after the Exxon Valdez oil spill, if observers fail to discriminate between direct mortality and shock-induced mortality. PMID:20089299

  15. Exposure of pink salmon embryos to dissolved polynuclear aromatic hydrocarbons delays development, prolonging vulnerability to mechanical damage.

    PubMed

    Carls, Mark G; Thedinga, John F

    2010-06-01

    Exposure to dissolved polynuclear aromatic hydrocarbons (PAHs) from crude oil delays pink salmon (Oncorhynchus gorbuscha) embryo development, thus prolonging their susceptibility to mechanical damage (shock). Exposure also caused mortality, edema, and anemia consistent with previous studies. Hatching and yolk consumption were delayed, indicating the rate of embryonic development was slowed by PAH exposure. The net result was that exposed embryos were more susceptible to shock than normal, unexposed embryos. Susceptibility to shock was protracted by 4-6d for more than a month in embryos exposed to exponentially declining, dissolved PAH concentrations in water passed through oiled rock; the initial total PAH concentration was 22.4microgL(-1) and the geometric mean concentration was 4.5microgL(-1) over the first 20d. Protracted susceptibility to shock caused by exposure to PAHs dissolved from oil could potentially increase the reported incidence of mortality in oiled stream systems, such as those in Prince William Sound after the Exxon Valdez oil spill, if observers fail to discriminate between direct mortality and shock-induced mortality.

  16. Prolonged Oxaliplatin Exposure Alters Intracellular Calcium Signaling: A New Mechanism To Explain Oxaliplatin-Associated Peripheral Neuropathy

    PubMed Central

    Schulze, Christin; McGowan, Margit; Jordt, Sven; Ehrlich, Barbara E

    2012-01-01

    Oxaliplatin is a platinum based cytotoxic agent commonly used to treat colorectal cancers. Despite its effectiveness, oxaliplatin administration is associated with the development of cold-induced peripheral neuropathy. This potentially permanent side effect is provoked by cold exposure and can range from mild and self limited to severe and debilitating. Even with tumor shrinkage, these painful side effects can force dose-reduction or discontinuation of treatment. Neither the mechanism of action of oxaliplatin nor that of cold-induced neuropathy is understood. Paclitaxel, an entirely different chemotherapeutic agent used to treat a variety of malignancies, also is associated with the development of peripheral neuropathy. Unlike oxaliplatin, neurotoxicity arising from paclitaxel treatment is better understood and was found to have profound effects on intracellular calcium signaling (1,2). In this study we examined the effects of oxaliplatin on calcium signaling pathways and found that acute exposure of either a neuroblastoma cell line or primary neurons with therapeutic concentrations of oxaliplatin had no effect on intracellular calcium signaling. We also found that cellular temperature sensors (TRP channels) were also not activated by oxaliplatin. Interestingly, prolonged exposure of oxaliplatin sensitized cells to subsequent stimuli and enhanced the magnitude of intracellular calcium responses. Taken together, our results suggest that acute oxaliplatin exposure will not induce abnormal calcium signaling but oxaliplatin-primed cells do exhibit enhanced sensitivity. These findings provide new insight to the mechanism behind oxaliplatin-induced neuropathy. PMID:21859566

  17. Evaluation of the CNS and cardiovascular effects of prolonged exposure to bromotrifluromethane (CBrF3)

    NASA Technical Reports Server (NTRS)

    Geller, I.; Garcia, C.; Gleiser, C.; Haines, R., Jr.; Hamilton, M.; Hartmann, R., Jr.; Mendez, V.; Samuels, A.; Miguel, M. S.

    1981-01-01

    The proposed use of bromotrifluoromethane (CBrF3) as a fire extinguishant in aircraft, spacecraft and submarines has stimulated increasing interest and research in the toxicological properties of this compound. In a spacecraft, because of its unique recirculating life support system, the introduction of CBrF3 by leakage or intentional discharge, will result in continuous exposure of crewman to low concentrations of this compound for periods of up to 7 days, or possibly even longer. The effects of low concentrations of CBrF3, under continuous exposure conditions, on the CNS and cardiovascular systems of animals to enable an assessment of these risks were investigated.

  18. Comparative cellular toxicity of titanium dioxide nanoparticles on human astrocyte and neuronal cells after acute and prolonged exposure.

    PubMed

    Coccini, Teresa; Grandi, Stefania; Lonati, Davide; Locatelli, Carlo; De Simone, Uliana

    2015-05-01

    Although in the last few decades, titanium dioxide nanoparticles (TiO₂NPs) have attracted extensive interest due to their use in wide range of applications, their influences on human health are still quite uncertain and less known. Evidence exists indicating TiO₂NPs ability to enter the brain, thus representing a realistic risk factor for both chronic and accidental exposure with the consequent needs for more detailed investigation on CNS. A rapid and effective in vitro test strategy has been applied to determine the effects of TiO₂NPs anatase isoform, on human glial (D384) and neuronal (SH-SY5Y) cell lines. Toxicity was assessed at different levels: mitochondrial function (by MTT), membrane integrity and cell morphology (by calcein AM/PI staining) after acute exposure (4-24-48 h) at doses from 1.5 to 250 μg/ml as well as growth and cell proliferation (by clonogenic test) after prolonged exposure (7-10 days) at sub-toxic concentrations (from 0.05 to 31 μg/ml). The cytotoxic effects of TiO₂NPs were compared with those caused by TiO₂ bulk counterpart treatment. Acute TiO₂NP exposure produced (i) dose- and time-dependent alterations of the mitochondrial function on D384 and SH-SY5Y cells starting at 31 and 15 μg/ml doses, respectively, after 24h exposure. SH-SY5Y were slightly more sensitive than D384 cells; and (ii) cell membrane damage occurring at 125 μg/ml after 24h exposure in both cerebral cells. Comparatively, the effects of TiO₂ bulk were less pronounced than those induced by nanoparticles in both cerebral cell lines. Prolonged exposure indicated that the proliferative capacity (colony size) was compromised at the extremely low TiO₂NP doses namely 1.5 μg/ml and 0.1 μg/ml for D384 and SH-SY5Y, respectively; cell sensitivity was still higher for SH-SY5Y compared to D384. Colony number decrease (15%) was also evidenced at ≥0.2 μg/ml TiO₂NP dose. Whereas, TiO₂ bulk treatment affected cell morphology only. TiO₂ internalization in SH

  19. Prolonged head-down tilt exposure reduces maximal cutaneous vasodilator and sweating capacity in humans

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Shibasaki, M.; Wilson, T. E.; Cui, J.; Levine, B. D.

    2003-01-01

    Cutaneous vasodilation and sweat rate are reduced during a thermal challenge after simulated and actual microgravity exposure. The effects of microgravity exposure on cutaneous vasodilator capacity and on sweat gland function are unknown. The purpose of this study was to test the hypothesis that simulated microgravity exposure, using the 6 degrees head-down tilt (HDT) bed rest model, reduces maximal forearm cutaneous vascular conductance (FVC) and sweat gland function and that exercise during HDT preserves these responses. To test these hypotheses, 20 subjects were exposed to 14 days of strict HDT bed rest. Twelve of those subjects exercised (supine cycle ergometry) at 75% of pre-bed rest heart rate maximum for 90 min/day throughout HDT bed rest. Before and after HDT bed rest, maximal FVC was measured, via plethysmography, by heating the entire forearm to 42 degrees C for 45 min. Sweat gland function was assessed by administering 1 x 10(-6) to 2 M acetylcholine (9 doses) via intradermal microdialysis while simultaneously monitoring sweat rate over the microdialysis membranes. In the nonexercise group, maximal FVC and maximal stimulated sweat rate were significantly reduced after HDT bed rest. In contrast, these responses were unchanged in the exercise group. These data suggest that 14 days of simulated microgravity exposure, using the HDT bed rest model, reduces cutaneous vasodilator and sweating capacity, whereas aerobic exercise training during HDT bed rest preserves these responses.

  20. Biologic effects of prolonged exposure to ELF electromagnetic fields in rats. 2: 50 Hz magnetic fields

    SciTech Connect

    Margonato, V.; Cerretelli, P.; Nicolini, P.; Conti, R.; Zecca, L.; Veicsteinas, Z.

    1995-12-31

    To provide possible laboratory support to health risk evaluation associated with long-term, low-intensity magnetic field exposure, 256 male albino rats and an equal number of control animals (initial age 12 weeks) were exposed 22 h/day to a 50 Hz magnetic flux density of 5 {micro}T for 32 weeks (a total of about 5,000 h). Hematology was studied from blood samples before exposure to the field and at 12 week intervals. Morphology and histology of liver, heart, mesenteric lymph nodes, and testes as well as brain neurotransmitters were assessed at the end of the exposure period. In two identical sets of experiments, no significant differences in the investigated variables were found between exposed and sham-exposed animals. It is concluded that continuous exposure to a 50 Hz magnetic field of 5 {micro}T from week 12 to week 44, which makes up {approximately}70% of the life span of the rat before sacrifice, does not cause changes in growth rate, in the morphology and histology of liver, heart, mesenteric lymph nodes, testes, and bone marrow, in hematology and hematochemistry, or in the neurotransmitters dopamine and serotonin.

  1. Mucous cell metaplasia in rat nasal epithelium after a 20-month exposure to ozone: A morphometric study of epithelial differentiation

    SciTech Connect

    Harkema, J.R.; Hotchkiss, J.A.; Griffith, W.C. |

    1997-12-31

    The present study was designed to examine the effects of long-term ozone exposure on nasal epithelia and intraepithelial mucosubstances (IM) throughout the nasal airways of F344/N rats. Animals were exposed to 0 (controls). 0. 12. 0.5, or 1.0 ppm ozone. 6 h/day, 5 days/wk. for 20 mo. Rats were killed 1 wk after the end of the exposure. and nasal tissues were processed for light and electron microscopy. Standard morphometric techniques were used to determine epithelial cell densities and the amounts of IM in the surface epithelium lining the nasal airways. No mucous cells or IM were present in the epithelia lining the nasal lateral meatus and maxillary sinus of rats exposed to 0 or 0.12 ppm ozone. In contrast, rats exposed to 0.5 or 1.0 ppm ozone had marked mucous cell metaplasia (MCM) with numerous mucous cells and conspicuous amounts of IM in the surface epithelium lining these upper airways. Ozone-induced increases in total epithelial cells (i.e., epithelial hyperplasia) were present only in rats exposed to 1.0 ppm. The results of this study indicate that rats chronically exposed to 1.0 or 0.5 ppm, but not 0. 121 ppm. ozone can develop marked MCM with significant increases in IM in both proximal and distal nasal airways. The epithelial chances observed throughout the nasal passages of ozone-exposed rats may be adaptive responses in an attempt to protect the upper and lower respiratory tract from further ozone-induced injury.

  2. Prior exposure to ozone potentiates subsequent response to sulfur dioxide in adolescent asthmatic subjects

    SciTech Connect

    Koenig, J.Q.; Covert, D.S.; Hanley, Q.S.; van Belle, G.; Pierson, W.E. )

    1990-02-01

    The objective of this study was to test whether prior exposure to a low concentration of ozone (120 ppb) would condition airways in asthmatic subjects to respond to a subthreshold concentration of sulfur dioxide (100 ppb). Eight male and five female subjects 12 to 18 yr of age participated. They all had allergic asthma and exercise-induced bronchospasm. Subjects were exposed to three test atmosphere sequences during intermittent moderate exercise (a 45-min exposure to one pollutant followed by a 15-min exposure to the second pollutant). The sequences were: air followed by 100 ppb SO2, 120 ppb O3 followed by 120 ppb O3, and 120 ppb O3 followed by 100 ppb SO2. The pulmonary function measurements assessed were FEV1, total respiratory resistance (RT), and maximal flow (Vmax50). Air-SO2 and O3-O3 exposures did not cause significant changes in pulmonary function. On the other hand, exposure to 100 ppb SO2 after a 45-min exposure to 120 ppb O3 caused a significant (8%) decrease in FEV1 (p = 0.046), a significant (19%) increase in RT (p = 0.048), and a significant (15%) decrease in Vmax50 (p = 0.008). It is concluded that prior O3 exposure increased bronchial hyperresponsiveness in these subjects such that they responded to an ordinarily subthreshold concentration of SO2. These data suggest that assessment of pulmonary changes to single pollutant challenges overlooks the interactive effects of common coexisting or sequentially occurring air pollutants.

  3. Combining group-based exposure therapy with prolonged exposure to treat U.S. Vietnam veterans with PTSD: a case study.

    PubMed

    Ready, David J; Vega, Edward M; Worley, Virginia; Bradley, Bekh

    2012-10-01

    Group-based exposure therapy (GBET) of 16-week duration was developed to treat combat-related posttraumatic stress disorder (PTSD) and decreased PTSD symptoms in 3 noncontrolled open trials with low attrition (0%-5%). Group-based exposure therapy has not produced as much PTSD symptom reduction as Prolonged Exposure (PE) within a U.S. Veterans Affairs PTSD treatment program, although PE had more dropouts (20%). This pilot study was of a model that combined key elements of GBET with components of PE in an effort to increase the effectiveness of a group-based treatment while reducing its length and maintaining low attrition. Twice per week, 8 Vietnam combat veterans with PTSD were treated for 12 weeks, with an intervention that included 2 within-group war trauma presentations per participant, 6 PE style individual imaginal exposure (IE) sessions per participant, daily listening to recorded IE sessions, and daily in vivo exposure exercises. All completed treatment and showed Significant reductions on all measures of PTSD with large effect sizes; 7 participants no longer met PTSD criteria on treating clinician administered interviews and a self-report measure at posttreatment. Significant reductions in depression with large effect sizes and moderate reductions in PTSD-related cognitions were also found. Most gains were maintained 6 months posttreatment. PMID:22965936

  4. Pre-exposure to ozone predisposes oak leaves to attacks by Diplodia corticola and Biscogniauxia mediterranea.

    PubMed

    Paoletti, Elena; Anselmi, Naldo; Franceschini, Antonio

    2007-01-01

    One-year-old cork oak (Quercus suber) and turkey oak (Q. cerris) seedlings were exposed to ozone (110 ppb, 5 h day(-1), for 30 days) and were inoculated with Diplodia corticola and Biscogniauxia mediterranea, respectively, by spraying a suspension of spores on the leaves. Both fungi are endophytic and may act as weak parasites, contributing to oak decline. Ozone exposure stimulated leaf attacks after inoculation, although the physiological, visible, and structural responses of both oaks to O3 exposure were weak. In fact, steady-state gas exchange, leaf waxes, and wettability were not significantly affected by O3. In Q. cerris, O3 altered the structure of stomata, as observed by scanning microscopy, and reduced the leaf relative water content. No hyphal entry through stomata or growth towards stomata was, however, observed. Inoculations were performed in a humid chamber at low light; stomata were likely to be closed. When Q. cerris was inoculated in natural conditions, i.e., in a forest infected by B. mediterranea, seedlings pre-exposed to the enhanced O3 regime had a higher number of B. mediterranea isolates than the controls. This suggests that pre-exposure to O3 predisposed Q. cerris leaves to attacks by B. mediterranea independent of stomata. The hyphae of both fungi were able to enter the leaf through the cuticle, either by gradual in-growth into the cuticle or erosion of a hollow in the cuticle at the point of contact. The primary cause of increased leaf injury in O3-exposed seedlings appeared to be higher germination of spores than on control leaves.

  5. Ozone exposure and daily mortality in Mexico City: a time-series analysis.

    PubMed

    Loomis, D P; Borja-Aburto, V H; Bangdiwala, S I; Shy, C M

    1996-10-01

    Daily death counts in Mexico City were examined in relation to ambient ozone levels during 1990-1992 for the purpose of investigating the acute, irreversible effects of air pollution, with emphasis on ozone exposure. Air pollution data were obtained from nine monitoring stations operated by the Departamento del Distrito Federal. Mortality data were provided by the Instituto Nacional de Estadística, Geografía, e Informática. Increases in numbers of deaths were positively associated with elevated air pollution levels on the same day and on the previous day. The magnitude of the increases was small but statistically significant, after Poisson regression models were used to adjust for temperature and long-term trends. In models using data for a single pollutant, the "crude" ratio for total mortality associated with an increase of 100 parts per billion (ppb)* in one-hour maximum ozone concentration was 1.029 (95% CI 1.015, 1.044). A moving average of ozone showed a stronger association (rate ratio [RR] = 1.048, 95% CI 1.025, 1.070), and excess mortality (an increase in the number of deaths, relative to the average on days with low pollution levels) was more evident for persons over 65 years of age. Separate analyses of the effect of elevated ozone for different areas of the city showed similar results, but they were not statistically significant. Other pollutants also were related to mortality. The RR was 1.075 (95% CI 0.984, 1.062) per 100-ppb increase for sulfur dioxide and 1.049 (95% CI 1.030, 1.067) per 100 micrograms/m3 increase in total suspended particulates (TSP) when these pollutants were considered in separate models. However, when all three pollutants were considered simultaneously, only TSP remained associated with mortality, indicating excess mortality of 5% per 100 micrograms/m3 increase [RR = 1.052, 95% CI 1.034, 1.072]. The excess mortality associated with TSP is consistent with that observed in other cities in America and Europe. This study provides

  6. In vivo ozone exposure induces antioxidant/stress-related responses in murine lung and skin.

    PubMed

    Valacchi, Giuseppe; Pagnin, Elisa; Corbacho, Ana M; Olano, Estibaliz; Davis, Paul A; Packer, Lester; Cross, Carroll E

    2004-03-01

    Lung and skin are the organs directly exposed to environmental pollution. Ozone (O(3)) is a toxic, oxidant air pollutant, and exposure has been shown to induce antioxidant depletion as well as oxidation of lipids and proteins within the outermost skin layer (stratum corneum) and the lung respiratory tract lining fluids (RTLFs). To further define skin and lung responses to O(3) exposure, SKH-1 hairless mice were exposed to either 0.8 ppm of O(3) (a level occasionally reached in very polluted areas) or ambient air 6 h/day for 6 consecutive days. O(3) exposure resulted in the depletion of alpha-tocopherol in lung and plasma and induction in both skin and lung of heme oxygenase 1, cyclooxygenase 2, and proliferating cell nuclear antigen. O(3)-exposed animals showed a similar extent of upregulation of COX-2 and PCNA in lung and skin, whereas HO-1 was more responsive in skin than in lung (7-fold induction vs. 2-fold induction). In addition to these measures of response to oxidative stress, O(3) exposure led to the activation of nuclear factor kappaB measured as IkappaBalpha phosphorylation in both tissues. We conclude that in this model, O(3) at high pollutant levels is able to affect both lung and skin biology, inducing depletion of alpha-tocopherol and inducing stress-related responses in both skin epidermis and respiratory tract epithelium.

  7. Changes in airway permeability and responsiveness after exposure to ozone. [Sheep

    SciTech Connect

    Abraham, W.M.; Delehunt, J.C.; Yerger, L.; Marchette, B.; Oliver, W. Jr.

    1984-06-01

    The relationship between airway responsiveness and the permeability of histamine through the airways in conscious sheep after exposure to ozone (O/sub 3/ was examined). Airway responsiveness was assessed by measuring the change from baseline in mean pulmonary flow resistance following a controlled 2-min inhalation challenge with 1% histamine, containing 200 ..mu..Ci/ml of (/sup 3/H)histamine. The rate of appearance of the (/sup 3/H)histamine in the plasma during inhalation challenge was used to estimate airway permeability. To perturb the airways, conscious sheep were exposed to either 0.5 or 1.0 ppm O/sub 3/ for 2 hr via an endotracheal tube. Airway responsiveness and airway permeability were measured prior to and 1 day after exposure. In six sheep exposed to 0.5 ppm O/sub 3/, increased airway responsiveness and airway permeability were obseved 1 day after exposure. Four of seven sheep exposed to 1.0 ppm O/sub 3/ had enhanced airway responsiveness and airway permeability, while the remaining three sheep showed corresponding decreases in airway responsiveness and airway permeability. Since the O/sub 3/-induced directional changes in airway responsiveness paralleled the directional changes in airway permeability in both the positive and negative directions, it was concluded that changes in airway responsiveness to inhaled histamine following exposure to O/sub 3/ may be related to concomitant changes in airway permeability to this agent.

  8. A special type of scald caused by prolonged exposure to slowly heated water.

    PubMed

    Pircher, R; Pollak, S; Vogt, S; Epting, T; Kramer, L; Geisenberger, D

    2016-06-01

    When skin is subjected to water temperatures gradually rising from moderate to critical ranges for a prolonged period of time, the resulting scalds will initially present as reddening, followed by blistering and at last by full-thickness burns. On changing from second- to third-degree burn, the blisters stop to become enlarged and solidify due to heat-induced coagulation necrosis. Such gradually intensifying tissue damage results in multiple firm skin blisters together with third-degree burn of the affected area. The initially serous blister fluid assumes a jelly-like consistency as the proteins undergo denaturation. Scalds of this special type may occur in persons taking a bath and becoming incapable to act so that the warm water tap remains turned on or a hairdryer continues to work after having been dropped into the bath water. On the basis of two relevant fatalities (suicidal electrocutions in bathtubs by means of hairdryers), the macroscopic and histological appearance of blisters which only secondarily turned into a full-thickness scald is compared with blisters in genuine second-degree scalds. The blister fluid of the latter ones was also investigated as to their protein composition and hemoglobin concentration. PMID:27129143

  9. Can prolonged exposure to low VPD disturb the ABA signalling in stomatal guard cells?

    PubMed Central

    Aliniaeifard, Sasan; van Meeteren, Uulke

    2013-01-01

    The response of stomata to many environmental factors is well documented. Multiple signalling pathways for abscisic acid (ABA)-induced stomatal closure have been proposed over the last decades. However, it seems that exposure of a leaf for a long time (several days) to some environmental conditions generates a sort of memory in the guard cells that results in the loss of suitable responses of the stomata to closing stimuli, such as desiccation and ABA. In this review paper we discuss changes in the normal pattern of signal transduction that could account for disruption of guard cell signalling after long-term exposure to some environmental conditions, with special emphasis on long-term low vapour pressure deficit (VPD). PMID:23956410

  10. Survival of the anaerobic fungus Orpinomyces sp. strain C1A after prolonged air exposure.

    PubMed

    Struchtemeyer, Christopher G; Ranganathan, Abhaya; Couger, M B; Liggenstoffer, Audra S; Youssef, Noha H; Elshahed, Mostafa S

    2014-01-01

    Anaerobic fungi are efficient plant biomass degraders and represent promising agents for a variety of biotechnological applications. We evaluated the tolerance of an anaerobic fungal isolate, Orpinomyces sp. strain C1A, to air exposure in liquid media using soluble (cellobiose) and insoluble (dried switchgrass) substrates. Strain C1A grown on cellobiose survived for 11, and 13.5 hours following air exposure when grown under planktonic, and immobilized conditions, respectively. When grown on switchgrass media, strain C1A exhibited significantly enhanced air tolerance and survived for 168 hours. The genome of strain C1A lacked a catalase gene, but contained superoxide dismutase and glutathione peroxidase genes. Real time PCR analysis indicated that superoxide dismutase, but not glutathione peroxidase, exhibits a transient increase in expression level post aeration. Interestingly, the C1A superoxide dismutase gene of strain C1A appears to be most closely related to bacterial SODs, which implies its acquisition from a bacterial donor via cross kingdom horizontal gene transfer during Neocallimastigomycota evolution. We conclude that strain C1A utilizes multiple mechanisms to minimize the deleterious effects of air exposure such as physical protection and the production of oxidative stress enzymes. PMID:25367149

  11. Survival of the anaerobic fungus Orpinomyces sp. strain C1A after prolonged air exposure

    PubMed Central

    Struchtemeyer, Christopher G.; Ranganathan, Abhaya; Couger, M. B.; Liggenstoffer, Audra S.; Youssef, Noha H.; Elshahed, Mostafa S.

    2014-01-01

    Anaerobic fungi are efficient plant biomass degraders and represent promising agents for a variety of biotechnological applications. We evaluated the tolerance of an anaerobic fungal isolate, Orpinomyces sp. strain C1A, to air exposure in liquid media using soluble (cellobiose) and insoluble (dried switchgrass) substrates. Strain C1A grown on cellobiose survived for 11, and 13.5 hours following air exposure when grown under planktonic, and immobilized conditions, respectively. When grown on switchgrass media, strain C1A exhibited significantly enhanced air tolerance and survived for 168 hours. The genome of strain C1A lacked a catalase gene, but contained superoxide dismutase and glutathione peroxidase genes. Real time PCR analysis indicated that superoxide dismutase, but not glutathione peroxidase, exhibits a transient increase in expression level post aeration. Interestingly, the C1A superoxide dismutase gene of strain C1A appears to be most closely related to bacterial SODs, which implies its acquisition from a bacterial donor via cross kingdom horizontal gene transfer during Neocallimastigomycota evolution. We conclude that strain C1A utilizes multiple mechanisms to minimize the deleterious effects of air exposure such as physical protection and the production of oxidative stress enzymes. PMID:25367149

  12. Cognitive and Affective Predictors of Treatment Outcome in Cognitive Processing Therapy and Prolonged Exposure for Posttraumatic Stress Disorder

    PubMed Central

    Rizvi, Shireen L.; Vogt, Dawne S.; Resick, Patricia A.

    2009-01-01

    This study examined cognitive and affective predictors of treatment dropout and treatment efficacy in Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE) for PTSD. Study participants were women with PTSD from a sexual assault who received at least one session of either treatment (n=145) as part of a randomized clinical trial. Results revealed that younger age, lower intelligence, and less education were associated with higher treatment dropout, whereas higher depression and guilt at pretreatment were associated with greater improvement in PTSD symptomatology. Results by treatment condition indicated that women with higher anger at pretreatment were more likely to drop out of PE and that older women in PE and younger women in CPT had the best overall outcomes. These findings have implications for efforts to enhance treatment efficacy and retention in CBT treatment protocols. PMID:19595295

  13. Cognitive and affective predictors of treatment outcome in Cognitive Processing Therapy and Prolonged Exposure for posttraumatic stress disorder.

    PubMed

    Rizvi, Shireen L; Vogt, Dawne S; Resick, Patricia A

    2009-09-01

    This study examined cognitive and affective predictors of treatment dropout and treatment efficacy in Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE) for PTSD. Study participants were women with PTSD from a sexual assault who received at least one session of either treatment (n = 145) as part of a randomized clinical trial. Results revealed that younger age, lower intelligence, and less education were associated with higher treatment dropout, whereas higher depression and guilt at pretreatment were associated with greater improvement in PTSD symptomatology. Results by treatment condition indicated that women with higher anger at pretreatment were more likely to dropout of PE and that older women in PE and younger women in CPT had the best overall outcomes. These findings have implications for efforts to enhance treatment efficacy and retention in CBT treatment protocols. PMID:19595295

  14. Morpho-pathological and physiological changes of the brain and liver after ozone exposure.

    PubMed

    Creţu, Denisa Ioana; Sovrea, Alina; Ignat, R M; Filip, Adriana; Bidian, Cristina; Creţu, Aurica

    2010-01-01

    This paper presents the consequences of long exposure to ozone in order to draw attention to this matter as far as the brain and liver are concerned. The material used was represented by two batches of 10 rats each that were daily exposed to ozone for 10 minutes at 0.5 ppm O3. From the first group blood was collected after two weeks to determine the indicators of oxidative stress and samples of brain and liver were drawn for histological studies. Tissue changes were highlighted using Hematoxylin-Eosin and argentic impregnation. In addition, the brain and liver samples taken from study subjects were turned into homogeneous preparations in order to determine the intensity of oxidative stress occurred in these organs compared with the witness group. The second batch was exposed for a further two weeks, after which the same sampling techniques and determining methods as for the first group were applied. The results show a correlation between the values of malondialdehyde (MDA) and glutathione (GSH), obtained both in blood and in the homogeneous preparations, and the microscopic changes that implicate a pathological state. Therefore, cerebral edema was discovered in the brain hemispheres and the cerebellum indicating necrotic signs accompanied by a reduction in the molecular layer and Purkinje cells with pale core. The liver presented hepatocellular necrosis, extended from the port area to the centrolobular vein.

  15. Reduced exercise time in competitive simulations consequent to low level ozone exposure

    SciTech Connect

    Schelegle, E.S.; Adams, W.C.

    1986-08-01

    Ten highly trained endurance athletes were studied to determine the effects of exposure to low ozone (O/sub 3/) concentrations on simulated competitive endurance performance and associated physiological and subjective symptom responses. Each subject was randomly exposed to filtered air (FA), and to 0.12, 0.18, and 0.24 ppm O/sub 3/ while performing a 1 h competitive simulation protocol on a bicycle ergometer. Endurance performance was evaluated by the number of subjects unable to complete rides (last 30 min at an intense work load of approximately 86% VO/sub 2/max). All subjects completed the FA exposure, whereas one, five, and seven subjects did not complete the 0.12, 0.18, and 0.24 ppm O/sub 3/ exposures, respectively. Statistical analysis indicated a significant (P less than 0.05) increase in the inability of subjects to complete the competitive simulations with increasing O/sub 3/ concentration, including a significant difference between the 0.24 ppm O/sub 3/ and FA exposure. Significant decreases (P less than 0.05) were also observed following the 0.18 and 0.24 ppm O/sub 3/ exposures, respectively, in forced vital capacity (-7.8 and -9.9%), and forced expiratory volume in 1 s (-5.8 and -10.5%). No significant O/sub 3/ effect was observed for exercise respiratory metabolism or ventilatory pattern responses. However, the number of reported subjective symptoms increased significantly following the 0.18 and 0.24 ppm O/sub 3/ protocols. These data demonstrate significant decrements in simulated competitive endurance performance and in pulmonary function, with accompanying enhanced subjective symptoms, following exposure to low O/sub 3/ levels commonly observed in numerous metropolitan environments during the summer months.

  16. Ozone-exposure depletes vitamin E and induces lipid peroxidation in murine stratum corneum.

    PubMed

    Thiele, J J; Traber, M G; Polefka, T G; Cross, C E; Packer, L

    1997-05-01

    The presence of ozone (O(3)) in photochemical smog is an important health concern. We hypothesized that the stratum corneum (SC), as the outermost skin layer and the permeability barrier of the skin, represents a sensitive target for O(3)-induced oxidative stress. To test this hypothesis, SKH-1 hairless mice were anesthetized and exposed for 2 h to O(3) by using two strategies: (i) single exposures to 0 (n = 12), 1 (n = 4), 5 (n = 4), and 10 (n = 4) ppm; and (ii) repeated daily exposures to 0 ppm (controls; n = 4) and 1 ppm (n = 4) for six consecutive days. New techniques based on the removal of SC by tape stripping were used to analyze the biologic effects of O(3) with respect to vitamin E depletion and lipid peroxidation. SC tissue was extracted from the tape and immediately analyzed by HPLC for vitamin E and malondialdehyde (MDA) concentrations. After in vivo exposure to increasing O(3) doses, vitamin E was depleted and MDA formation was increased, both in a dose-dependent manner. Remarkably, repeated low-level O(3) exposures resulted in cumulative oxidative effects in the SC: As compared with O(3) exposures of 0 ppm (alpha-tocopherol, 8.95 +/- 1.3 pmol per mg; gamma-tocopherol, 3.00 +/- 0.3 pmol per mg; MDA, 3.69 +/- 0.3 pmol per mg), vitamin E was depleted (alpha-tocopherol, 2.90 +/- 0.6 pmol per mg, p < 0.001; gamma-tocopherol, 0.5 +/- 0.1 pmol per mg, p < 0.001) and MDA levels were increased (4.5 +/- 0.2; p < 0.01). This report demonstrates the unique susceptibility of the SC to oxidative damage upon exposure to O(3).

  17. Changes in thyroid status of rats after prolonged exposure to low dose dichlorodiphenyltrichloroethane.

    PubMed

    Yaglova, N V; Yaglov, V V

    2014-04-01

    The effect of low dose dichlorodiphenyltrichloroethane (DDT), omnipresent ecotoxicant and endocrine disruptor, on the functioning of the endocrine system is an urgent problem. We studied the effect of low dose DDT on thyroid status in rats. Rats receiving DDT in a dose of 1.890±0.086 μg/kg for 6 weeks showed increased concentrations of thyroid hormones, particularly triiodothyronine, and reduced level of thyrotropin. Longer exposure reduced the production of thyroid hormones. The dynamics of thyroid status parameters during DDT treatment in a low dose was similar to changes observed during the development of hypothyroidism induced by iodine deficiency. PMID:24824690

  18. Effect of Same-day Sequential Exposure to Nitrogen Dioxide and Ozone on Cardiac and Ventilatory Function in Mice

    EPA Science Inventory

    This study examines the cardiac and ventilatory effects of sequential exposure to nitrogen dioxide and then ozone. The data show that mice exposed to both gases have increased arrhythmia and breathing changes not observed in the other groups. Although the mechanisms underlying ai...

  19. INTERPOLATION OF TEMPERATURE AND NON-URBAN OZONE EXPOSURE AT HIGH SPATIAL RESOLUTION OVER THE WESTERN UNITED STATES

    EPA Science Inventory

    In order to assess the impact of natural and anthropogenic stresses on forest ecosystems, it is necessary to interpolate air temperature and tropospheric ozone (O3) exposure values at high spatial resolution over complex terrain. The proposed interpolation approach was selected ...

  20. Ozone exposure response for U.S. soybean cultivars: linear reductions in photosynthetic potential, biomass and yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current background ozone concentrations ([O3]) over the Northern Hemisphere’s mid-latitudes are high enough to damage crops, and are projected to increase. Soybean (Glycine max [L.] Merr.) is particularly sensitive to O3 therefore establishing an O3 exposure-threshold for damage is critical to under...

  1. Effects of prolonged exposure of lettuce seeds to HZE particles on orbital stations

    NASA Astrophysics Data System (ADS)

    Nevzgodina, L. V.; Maksimova, E. N.; Kaminskaya, E. V.

    In a study of the biological effects of cosmic HZE particles, lettuce (Lactuca sativa) seeds were flown on the orbital stations Salyut 6 and 7 for varying periods of time (from 40 to 457 days). The dependence of the biological damage on flight duration, physical parameters and the fact of passage of an HZE particle through the seed was estimated using the criterion of the frequency of aberrant cells. The arrangement of the flight biological container Biobloc made it possible to trace the location of tracks of individual HZE particles with Z>=6 and LET 200 keV/um. In seeds hit by HZE particles, for all exposure times, a statistically significant much higher yield of aberrant cells and also of cells containing multiple chromosome aberrations was observed than in the control material. The frequency of aberrant cells is markedly higher (by a factor of 1,5) in seeds hit than in non-hit ones. The changes of the yield of aberrant cells as a function of the absorbed dose (3.2-63.4 mGy) and the fluence (4.8-44.2 particles/cm2) are linear for the exposure duration ranging from 40 to 457 days.

  2. Persistence of peak flow decrement in children following ozone exposures exceeding the national ambient air quality standard

    SciTech Connect

    Lioy, P.J.; Vollmuth, T.A.; Lippmann, M.

    1985-10-01

    A linear regression was calculated between the peak one-hour ozone concentration for a given day and forced vital capacity (FVC), forced expiratory volume in one second (FEV), and peak expiratory flow rate (PEFR) as determined the same day from spirograms for each of the 39 children tested on six or more days. All mean slopes were negative, except for FVC in boys, indicating a general tendency for decreased function with increasing ozone concentration. In another analysis, a summary weighted correlation coefficient between peak ozone level and each pulmonary function parameter was calculated for each of 49 children seen on four or more days. As in the regression analysis, decrements in PEFR were significantly correlated with the ozone exposure. Analysis of residuals from the regression lines provide evidence for responses of greater potential significance to the future health of the children. They indicate a different kind of response, i.e., a persistent decrement in function lasting for as much as a week after the end of a smog period of about four days' duration. The persistent effects associated with ozone could have been due to acidic sulfates as well as, or in addition to, ozone. 10 references, 2 figures, 2 tables.

  3. Relationships of ozone exposure to pine injury in the Sierra Nevada and San Bernardino Mountains of California, USA.

    PubMed

    Arbaugh, M J; Miller, P R; Carroll, J J; Takemoto, B; Procter, T

    1998-01-01

    Hourly ambient ozone exposure data and crown injury measurements were gathered in the Sierra Nevada and San Bernardino Mountains of California to develop relationships between the Ozone Injury Index (OII), the Forest Pest Management Index (FPM), chlorotic mottle, fascicle retention (OII index components) and cumulative ambient ozone indices for Pinus ponderosa Dougl. ex Laws and Pinus jeffreyi Grev. and Balf. Eleven sites located in the mixed conifer forest near ambient ozone monitoring sites were evaluated annually for 4 years. Four other sites in the San Bernardino Mountains were evaluated for 1 year. Analyses showed OII to be functionally equivalent (r2 = 0.96) to the FPM, and to depend only on fascicle retention and chlorotic mottle (R2 = 0.95) of the fourth whorl (or if four whorls are not present at the site, then the last whorl present for the majority of trees). Significant associations were found between OII and 4-year 24-h. summer SUM0, SUM06, W126 and HRS80 ozone indices. Three sites had higher levels of cumulative chlorotic mottle for individual whorls and larger numbers of trees with visible crown injury than other sites with similar cumulative ambient ozone levels. Including an indicator variable to discriminate between these two groups of sites increased R2 and decreased root mean square (RMSE) for all indices, especially SUM0 (R2 = 0.93, RMSE reduced by 46%). PMID:15093091

  4. Simulated Sensitivity of Seasonal Ozone Exposure in the Great Lakes Region to Changes in Anthropogenic Emissions in the Presence of Interannual Variability

    SciTech Connect

    Fast, Jerome D.; Heilman, Warren E.

    2005-09-01

    A coupled meteorological and chemical modeling system with a 12-km horizontal grid spacing was used to simulate the evolution of ozone over the Great Lakes region between May and September of 1999 and 2001. Model performance was evaluated using operational surface and upper-air meteorological measurements and surface ozone data. The overall temporal and spatial variations in hourly ozone concentrations and ozone exposure from control simulations agreed reasonably well with the observations at most locations. The simulated ozone exposure was higher during the summer of 1999 than during 2001, similar to the observations. The emission projection simulation that employed the meteorological conditions of 1999 and increased anthropogenic emissions projected for the year 2020 produced increases in ozone exceeding 80 ppb over the lower peninsula of Michigan, the eastern half of the upper peninsula of Michigan, and over Ontario just north of Lake Superior and Lake Huron. Relatively large increases in ozone exceeding 60 ppb were also produced over agricultural regions. Despite the projected increase in anthropogenic emissions for the year 2020, increases in ozone exceeding 60 ppb occurred only over the lake surfaces and in central Michigan when the meteorological conditions of the summer of 2001 were applied. The meteorological conditions during the summer of 2001 were not as favorable for ozone production and did not result in increased ozone. For both summers, increases in anthropogenic emissions projected for the year 2020 decreased ozone exposure in the immediate vicinity of the largest metropolitan areas. The simulated ozone from this study will be used in the near future as input to biological models to assess the response of ozone-sensitive tree species to current and future ozone levels in the Great Lakes region.

  5. Age-dependent inhibition of pentobarbital sleeping time by ozone in mice and rats

    SciTech Connect

    Canada, A.T.; Calabrese, E.J.; Leonard, D.

    1986-09-01

    The effect of age on the metabolism of pentobarbital in mice and rats was investigated following exposure to 0.3 ppm of ozone for 3.75 hr. Young animals were 2.5 months of age and the mature were 18 months. The pentobarbital sleeping time was significantly prolonged following the ozone exposure in both the mice and rats when compared with an air control. No ozone effect on sleeping time was found in the young animals. The results indicate that there may be an age-related sensitivity to the occurrence of ozone-related inhibition of pentobarbital metabolism.

  6. Design considerations for ozone and acid aerosol exposure and health investigations: the Fairview Lake summer camp - photochemical smog case study

    SciTech Connect

    Lioy, P.J.; Spektor, D.; Thurston, G.; Citak, K.; Lippmann, M.; Bock, N.; Speizer, F.E.; Hayes, C.

    1987-01-01

    The health effects associated with ozone and acidic particulate sulfate exposures to active children have been and are being addressed in field epidemiological studies at summer camps in rural areas of the Northeastern US. The rationale and study design for studies, which have been conducted in Pennsylvania and New Jersey, are developed and reviewed. As background, results are summarized for human clinical and epidemiological studies and animal studies. These provided the basis for selection of health outcomes measured results from chemical characterization and transport studies are reviewed to define the criteria used for selection of a site which is effected by high ozone and acid species during photochemical smog episodes. The integration of the study design is discussed in detail by reviewing its application to the 1984 - Fairview Lake Camp Study (July 8 to August 4). The features of the camp study are reviewed, including the study population, pulmonary function procedures and analyses, air pollution monitoring instrumentation, and the site characteristics. The pollution exposure data are presented, for ozone and acidic sulfates and examined for the range and distribution concentration. Further information is provided on the intensity and duration of episodes encountered over the course of the study. Episodes occurred which had ozone and acid sulfates, ozone alone, and acid sulfates alone. 56 references, 9 figures.

  7. Enhanced response to ozone exposure during the follicular phase of the menstrual cycle

    SciTech Connect

    Fox, S.D.; Adams, W.C.; Brookes, K.A.; Lasley, B.L. )

    1993-08-01

    Exposure to ozone (O[sub 3]), a toxic component of photochemical smog, results in significant airway inflammation, respiratory discomfort, and pulmonary function impairment. These effects can be reduced via pretreatment with anti-inflammatory agents. Progesterone, a gonadal steroid, is known to reduce general inflammation in the uterine endometrium. However, it is not known whether fluctuation in blood levels of progesterone, which are experienced during the normal female menstrual cycle, could alter O[sub 3] inflammatory-induced pulmonary responses. In this study, we tested the hypothesis that young, adult females are more responsive to O[sub 3] inhalation with respect to pulmonary function impairment during their follicular (F) menstrual phase when progesterone levels are lowest that during their mid-luteal (ML) phase when progesterone levels are highest. Nine subjects with normal ovarian function were exposed in random order for 1 hour each to filtered air and to 0.30 ppm O[sub 3] in their F and ML menstrual phases. Ozone responsiveness was measured by percent change in pulmonary function from pre- to postexposure. Significant gas concentration effects (filtered air versus O[sub 3]) were observed for forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV[sub 1]), and forced expiratory flow between 25 and 75% of FVC (FEF[sub 25-75]), showed a significant menstrual phase and gas concentration interaction effect, with larger decrements observed in the F menstrual phase when progesterone concentrations were significantly lower. We conclude that young, adult females appear to be more responsive to acute O[sub 3] exposure during the F phase than during the ML phase of their menstrual cycles. This difference in pulmonary function response could be related to the anti-inflammatory effects of increased progesterone concentrations during the luteal phase.

  8. Exposure to environmentally-relevant levels of ozone negatively influence pollen and fruit development.

    PubMed

    Gillespie, Colin; Stabler, Daniel; Tallentire, Eva; Goumenaki, Eleni; Barnes, Jeremy

    2015-11-01

    A combination of in vitro and in vivo studies on tomato (Lycopersicon esculentum Mill. cv. Triton) revealed that environmentally-relevant levels of ozone (O3) pollution adversely affected pollen germination, germ tube growth and pollen-stigma interactions - pollen originating from plants raised in charcoal-Purafil(®) filtered air (CFA) exhibited reduced germ tube development on the stigma of plants exposed to environmentally-relevant levels of O3. The O3-induced decline in in vivo pollen viability was reflected in increased numbers of non-fertilized and fertilized non-viable ovules in immature fruit. Negative effects of O3 on fertilization occurred regardless of the timing of exposure, with reductions in ovule viability evident in O3 × CFA and CFA × O3 crossed plants. This suggests O3-induced reductions in fertilization were associated with reduced pollen viability and/or ovule development. Fruit born on trusses independently exposed to 100 nmol mol(-1) O3 (10 h d(-1)) from flowering exhibited a decline in seed number and this was reflected in a marked decline in the weight and size of individual fruit - a clear demonstration of the direct consequence of the effects of the pollutant on reproductive processes. Ozone exposure also resulted in shifts in the starch and ascorbic acid (Vitamin C) content of fruit that were consistent with accelerated ripening. The findings of this study draw attention to the need for greater consideration of, and possibly the adoption of weightings for the direct impacts of O3, and potentially other gaseous pollutants, on reproductive biology during 'risk assessment' exercises.

  9. Comparison of the responses of children and adults to acute ozone exposure

    SciTech Connect

    McDonnell, W.F.; Chapman, R.S.; Horstman, D.H.; Leigh, M.W.; Salaam, S.A.

    1986-07-01

    The purpose of the paper is to compare the results of two studies in which the respiratory responses of children and adults to acute ozone (O/sub 3/) exposure were measured. Forty-two 18-30 year old males were exposed for 2.5 hours in a controlled environmental chamber to either 0.0 or 0.12 ppm O3 while performing intermittent heavy exercise. Twenty-two 8-11 year old males were exposed in a similar manner to both air and 0.12 ppm O3. Measures of respiratory symptoms and function were made before and after exposure. Adults experienced an increase in the symptom cough and decrements in forced vital capacity and some measures of forced expiratory flow. Children experienced similar decrements in pulmonary function, but had no increase in symptoms. The authors concluded that as measured by pulmonary function children appear to be no more responsive to O3 exposure than are adults and may experience fewer symptoms.

  10. Effect of cadmium on blood of tilapia, Oreochromis mossambicus (Peters), during prolonged exposure

    SciTech Connect

    Ruparelia, S.G.; Verma, Y.; Saiyed, S.R. ); Rawal, U.M. )

    1990-08-01

    Cadmium is recognized as one of the most hazardous environmental pollutants and is toxic to many living organisms. Experimental and environmental exposure to cadmium has been reported to cause disease in humans and other mammals. Recent reviews on cadmium have reported on acute and subacute effects on fish, mechanisms of toxicity, the role of toxicity modifying factors and various sublethal effects, i.e., hematological and biochemical disorders. However, very little information is available on the subacute effects of cadmium on fish blood exposed in hard water. The present investigation, therefore, was carried out to observe the effects of cadmium on the blood of tilapia (Oreochromis mossambicus) in hard and alkaline water to determine whether cadmium causes changes in blood of fish kept in hard water in the same way it causes changes in blood of fish kept in soft water.

  11. Resistin deficiency in mice has no effect on pulmonary responses induced by acute ozone exposure.

    PubMed

    Razvi, Shehla S; Richards, Jeremy B; Malik, Farhan; Cromar, Kevin R; Price, Roger E; Bell, Cynthia S; Weng, Tingting; Atkins, Constance L; Spencer, Chantal Y; Cockerill, Katherine J; Alexander, Amy L; Blackburn, Michael R; Alcorn, Joseph L; Haque, Ikram U; Johnston, Richard A

    2015-11-15

    Acute exposure to ozone (O3), an air pollutant, causes pulmonary inflammation, airway epithelial desquamation, and airway hyperresponsiveness (AHR). Pro-inflammatory cytokines-including IL-6 and ligands of chemokine (C-X-C motif) receptor 2 [keratinocyte chemoattractant (KC) and macrophage inflammatory protein (MIP)-2], TNF receptor 1 and 2 (TNF), and type I IL-1 receptor (IL-1α and IL-1β)-promote these sequelae. Human resistin, a pleiotropic hormone and cytokine, induces expression of IL-1α, IL-1β, IL-6, IL-8 (the human ortholog of murine KC and MIP-2), and TNF. Functional differences exist between human and murine resistin; yet given the aforementioned observations, we hypothesized that murine resistin promotes O3-induced lung pathology by inducing expression of the same inflammatory cytokines as human resistin. Consequently, we examined indexes of O3-induced lung pathology in wild-type and resistin-deficient mice following acute exposure to either filtered room air or O3. In wild-type mice, O3 increased bronchoalveolar lavage fluid (BALF) resistin. Furthermore, O3 increased lung tissue or BALF IL-1α, IL-6, KC, TNF, macrophages, neutrophils, and epithelial cells in wild-type and resistin-deficient mice. With the exception of KC, which was significantly greater in resistin-deficient compared with wild-type mice, no genotype-related differences in the other indexes existed following O3 exposure. O3 caused AHR to acetyl-β-methylcholine chloride (methacholine) in wild-type and resistin-deficient mice. However, genotype-related differences in airway responsiveness to methacholine were nonexistent subsequent to O3 exposure. Taken together, these data demonstrate that murine resistin is increased in the lungs of wild-type mice following acute O3 exposure but does not promote O3-induced lung pathology. PMID:26386120

  12. Pulmonary epithelial integrity in children: relationship to ambient ozone exposure and swimming pool attendance.

    PubMed

    Lagerkvist, Birgitta Json; Bernard, Alfred; Blomberg, Anders; Bergstrom, Erik; Forsberg, Bertil; Holmstrom, Karin; Karp, Kjell; Lundstrom, Nils-Goran; Segerstedt, Bo; Svensson, Mona; Nordberg, Gunnar

    2004-12-01

    Airway irritants such as ozone are known to impair lung function and induce airway inflammation. Clara cell protein (CC16) is a small anti-inflammatory protein secreted by the nonciliated bronchiolar Clara cells. CC16 in serum has been proposed as a noninvasive and sensitive marker of lung epithelial injury. In this study, we used lung function and serum CC16 concentration to examine the pulmonary responses to ambient O3 exposure and swimming pool attendance. The measurements were made on 57 children 10-11 years of age before and after outdoor exercise for 2 hr. Individual O3 exposure was estimated as the total exposure dose between 0700 hr until the second blood sample was obtained (mean O3 concentration/m3 times symbol hours). The maximal 1-hr value was 118 microg/m3 (59 ppb), and the individual exposure dose ranged between 352 and 914 microg/m3hr. These O3 levels did not cause any significant changes in mean serum CC16 concentrations before or after outdoor exercise, nor was any decrease in lung function detected. However, children who regularly visited chlorinated indoor swimming pools had significantly lower CC16 levels in serum than did nonswimming children both before and after exercise (respectively, 57 +/- 2.4 and 53 +/- 1.7 microg/L vs. 8.2 +/- 2.8 and 8.0 +/- 2.6 microg/L; p < 0.002). These results indicate that repeated exposure to chlorination by-products in the air of indoor swimming pools has adverse effects on the Clara cell function in children. A possible relation between such damage to Clara cells and pulmonary morbidity (e.g., asthma) should be further investigated.

  13. Increased CCL24/Eotaxin-2 with Postnatal Ozone Exposure in Allergen-Sensitized Infant Monkeys Is Not Associated with Recruitment of Eosinophils to Airway Mucosa

    PubMed Central

    Chou, Debbie L.; Gerriets, Joan E.; Schelegle, Edward S.; Hyde, Dallas M.; Miller, Lisa A.

    2011-01-01

    Epidemiology supports a causal link between air pollutant exposure and childhood asthma, but the mechanisms are unknown. We have previously reported that ozone exposure can alter the anatomic distribution of CD25+ lymphocytes in airways of allergen-sensitized infant rhesus monkeys. Here, we hypothesized that ozone may also affect eosinophil trafficking to allergen-sensitized infant airways. To test this hypothesis, we measured blood, lavage, and airway mucosa eosinophils in 3-month old monkeys following cyclical ozone and house dust mite (HDM) aerosol exposures. We also determined if eotaxin family members (CCL11, CCL24, CCL26) are associated with eosinophil location in response to exposures. In lavage, eosinophil numbers increased in animals exposed to ozone and/or HDM. Ozone + HDM animals showed significantly increased CCL24 and CCL26 protein in lavage, but the concentration of CCL11, CCL24, and CCL26 was independent of eosinophil number for all exposure groups. In airway mucosa, eosinophils increased with exposure to HDM alone; comparatively, ozone and ozone + HDM resulted in reduced eosinophils. CCL26 mRNA and immunofluorescence staining increased in airway mucosa of HDM alone animals and correlated with eosinophil volume. In ozone + HDM animal groups, CCL24 mRNA and immunofluorescence increased along with CCR3 mRNA, but did not correlate with airway mucosa eosinophils. Cumulatively, our data indicate that ozone exposure results in a profile of airway eosinophil migration that is distinct from HDM mediated pathways. CCL24 was found to be induced only by combined ozone and HDM exposure, however expression was not associated with the presence of eosinophils within the airway mucosa. PMID:21945493

  14. Prolonged exposure to methylglyoxal causes disruption of vascular KATP channel by mRNA instability

    PubMed Central

    Yang, Yang; Li, Shanshan; Konduru, Anuhya S.; Zhang, Shuang; Trower, Timothy C.; Shi, Weiwei; Cui, Ningren; Yu, Lei; Wang, Yali; Zhu, Daling

    2012-01-01

    Diabetes mellitus is characterized by hyperglycemia and excessive production of intermediary metabolites including methylglyoxal (MGO), a reactive carbonyl species that can lead to cell injuries. Interacting with proteins, lipids, and DNA, excessive MGO can cause dysfunction of various tissues, especially the vascular walls where diabetic complications often take place. However, the potential vascular targets of excessive MGO remain to be fully understood. Here we show that the vascular Kir6.1/SUR2B isoform of ATP-sensitive K+ (KATP) channels is likely to be disrupted with an exposure to submillimolar MGO. Up to 90% of the Kir6.1/SUR2B currents were suppressed by 1 mM MGO with a time constant of ∼2 h. Consistently, MGO treatment caused a vast reduction of both Kir6.1 and SUR2B mRNAs endogenously expressed in the A10 vascular smooth muscle cells. In the presence of the transcriptional inhibitor actinomycin-D, MGO remained to lower the Kir6.1 and SUR2B mRNAs to the same degree as MGO alone, suggesting that the MGO effect is likely to compromise the mRNA stability. Luciferase reporter assays indicated that the 3′-untranslated regions (UTRs) of the Kir6.1 but not SUR2 mRNA were targeted by MGO. In contrast, the SUR2B mRNAs obtained with in vitro transcription were disrupted by MGO directly, while the Kir6.1 transcripts were unaffected. Consistent with these results, the constriction of mesenteric arterial rings was markedly augmented with an exposure to 1 mM MGO for 2 h, and such an MGO effect was totally eliminated in the presence of glibenclamide. These results therefore suggest that acting on the 3′-UTR of Kir6.1 and the coding region of SUR2B, MGO causes instability of Kir6.1 and SUR2B mRNAs, disruption of vascular KATP channels, and impairment of arterial function. PMID:22972803

  15. Cultural adaptations of prolonged exposure therapy for treatment and prevention of posttraumatic stress disorder in african americans.

    PubMed

    Williams, Monnica T; Malcoun, Emily; Sawyer, Broderick A; Davis, Darlene M; Bahojb Nouri, Leyla; Bruce, Simone Leavell

    2014-06-01

    Posttraumatic stress disorder (PTSD) is a highly disabling disorder, afflicting African Americans at disproportionately higher rates than the general population. When receiving treatment, African Americans may feel differently towards a European American clinician due to cultural mistrust. Furthermore, racism and discrimination experienced before or during the traumatic event may compound posttrauma reactions, impacting the severity of symptoms. Failure to adapt treatment approaches to encompass cultural differences and racism-related traumas may decrease treatment success for African American clients. Cognitive behavioral treatment approaches are highly effective, and Prolonged Exposure (PE) in particular has the most empirical support for the treatment of PTSD. This article discusses culturally-informed adaptations of PE that incorporates race-related trauma themes specific to the Black experience. These include adding more sessions at the front end to better establish rapport, asking directly about race-related themes during the assessment process, and deliberately bringing to the forefront race-related experiences and discrimination during treatment when indicated. Guidelines for assessment and the development of appropriate exposures are provided. Case examples are presented demonstrating adaptation of PE for a survivor of race-related trauma and for a woman who developed internalized racism following a sexual assault. Both individuals experienced improvement in their posttrauma reactions using culturally-informed adaptations to PE.

  16. Cultural Adaptations of Prolonged Exposure Therapy for Treatment and Prevention of Posttraumatic Stress Disorder in African Americans

    PubMed Central

    Williams, Monnica T.; Malcoun, Emily; Sawyer, Broderick A.; Davis, Darlene M.; Bahojb Nouri, Leyla; Bruce, Simone Leavell

    2014-01-01

    Posttraumatic stress disorder (PTSD) is a highly disabling disorder, afflicting African Americans at disproportionately higher rates than the general population. When receiving treatment, African Americans may feel differently towards a European American clinician due to cultural mistrust. Furthermore, racism and discrimination experienced before or during the traumatic event may compound posttrauma reactions, impacting the severity of symptoms. Failure to adapt treatment approaches to encompass cultural differences and racism-related traumas may decrease treatment success for African American clients. Cognitive behavioral treatment approaches are highly effective, and Prolonged Exposure (PE) in particular has the most empirical support for the treatment of PTSD. This article discusses culturally-informed adaptations of PE that incorporates race-related trauma themes specific to the Black experience. These include adding more sessions at the front end to better establish rapport, asking directly about race-related themes during the assessment process, and deliberately bringing to the forefront race-related experiences and discrimination during treatment when indicated. Guidelines for assessment and the development of appropriate exposures are provided. Case examples are presented demonstrating adaptation of PE for a survivor of race-related trauma and for a woman who developed internalized racism following a sexual assault. Both individuals experienced improvement in their posttrauma reactions using culturally-informed adaptations to PE. PMID:25379272

  17. Glucose Homeostasis During Short-term and Prolonged Exposure to High Altitudes

    PubMed Central

    Ader, Marilyn; Bergman, Richard N.

    2015-01-01

    Most of the literature related to high altitude medicine is devoted to the short-term effects of high-altitude exposure on human physiology. However, long-term effects of living at high altitudes may be more important in relation to human disease because more than 400 million people worldwide reside above 1500 m. Interestingly, individuals living at higher altitudes have a lower fasting glycemia and better glucose tolerance compared with those who live near sea level. There is also emerging evidence of the lower prevalence of both obesity and diabetes at higher altitudes. The mechanisms underlying improved glucose control at higher altitudes remain unclear. In this review, we present the most current evidence about glucose homeostasis in residents living above 1500 m and discuss possible mechanisms that could explain the lower fasting glycemia and lower prevalence of obesity and diabetes in this population. Understanding the mechanisms that regulate and maintain the lower fasting glycemia in individuals who live at higher altitudes could lead to new therapeutics for impaired glucose homeostasis. PMID:25675133

  18. Effects of prolonged low-level cadmium exposure on the tadpole immune system.

    PubMed

    Zettergren, L D; Boldt, B W; Petering, D H; Goodrich, M S; Weber, D N; Zettergren, J G

    1991-01-01

    Uninjected (Group I) and sheep erythrocyte (SRBC)-injected (Group II) Rana tadpoles were exposed to varying sublethal concentrations of cadmium (Cd) for 6 weeks. In order to assess possible effects on the tadpole immune system we determined pre-B, B mu, and plasma cell (PC mu) frequencies in liver and mesonephros of Group I larvae, and hemagglutinating antibody (HA) titers of Group II animals. Group I and Group II control animals were cultivated in water with no added Cd (0 ppm), while treatments were set at 0.1, 0.2, 0.4 and 0.8 ppm Cd. We found that (a) Cd appeared to stimulate a significant increase in the frequency of B mu cells in animals treated at 0.4 and 0.8 ppm, (b) certain treated Group II larvae contained significantly increased amounts of HA in their serum, while their serum protein concentrations were not significantly different, and (c) there was a dose-related increase in tissue Cd levels in treated Group II larvae. Our observations suggest that chronic low-level exposure to Cd may (a) result in a slight increases in the frequency of B mu cells in unimmunized animals, (b) increase immune responsiveness of immunized larvae, and (c) increase liver and mesonephros accumulations of Cd. Preliminary studies indicated that cytosolic Cd is associated with a protein which appears to be similar to mammalian metallothionein.

  19. Factors involved in strain-induced injury in skeletal muscles and outcomes of prolonged exposures.

    PubMed

    Stauber, William T

    2004-02-01

    Repetitive motion disorders can involve lengthening of skeletal muscles to perform braking actions to decelerate limbs under load often resulting in muscle strains and injury. Injury is a loss of isometric force (weakness) requiring days to recover. The capacity of skeletal muscle to tolerate repeated strains is dependent on multiple factors including individual variation. The most important factors producing muscle strain injury are the magnitude of the resisting force (peak-stretch force) and the number of strains. Other factors such as muscle length and fiber type contribute to the susceptibility to injury as well, but to a lesser degree. Strain injury can also lead to inflammation and pain. Chronic exposure to repeated strains can result in fibrosis that is not completely reversed after months of rest. Long rest times appear to be the only factor reported to prevent inflammation in rats following repeated strain injury. Further understanding of the mechanism for prevention of histopathologic changes by long rest times should provide a rationale for prevention of negative outcomes.

  20. Changes in the carbon dioxide expirogram in response to ozone exposure

    SciTech Connect

    Taylor, Adekemi B.; Lee, Genea M.; Nellore, Kavitha; Ben-Jebria, Abdellaziz . E-mail: axb23@psu.edu; Ultman, James S.

    2006-05-15

    The objectives of this study were to quantify pulmonary responses to ozone (O{sub 3}) exposure by parameters computed from the carbon dioxide expirogram and to compare these responses to decrements in forced expired spirometry. Anatomical dead space (V {sub D}) was determined from the pure dead space and transition regions of the expirogram. Four alternative parameters were computed from the alveolar plateau: slope (S), normalized slope (NS), peripheral cross-sectional area (A {sub P}) and well-mixed peripheral volume (V {sub MP}). Forty-seven healthy nonsmokers (25 men and 22 women) participated in two research sessions in which they exercised on a cycle ergometer for 1 h while orally inhaling either room air at a minute ventilation of 30.6 {+-} 3.6 L or room air mixed with 0.252 {+-} 0.029 ppm O{sub 3} at a minute ventilation of 29.9 {+-} 3.7 L. Carbon dioxide expirograms were measured before exposure, 10 min after exposure and 70 min after exposure. Percent changes (mean {+-} SD) in expirogram parameters were significant (P {<=} 0.002) at both 10 and 70 min after O{sub 3} exposure: V {sub D}(-4.2 {+-} 5.1, -3.3 {+-} 6.9), S(16.4 {+-} 17.9, +15.1 {+-} 20.2), NS(17.5 {+-} 15.4, +15.9 {+-} 19.2), A {sub P}(-8.1 {+-} 7.6, -7.7 {+-} 9.8) and V {sub MP}(-15.4 {+-} 13.0, -13.0 {+-} 15.2). Percent decrements of forced expired volume in one second (FEV{sub 1}) were also significant at both 10 min (-13.3 {+-} 13.4) and 70 min (-11.1 {+-} 9.2) following O{sub 3} exposure. Changes in the expirogram as well as decrements in FEV{sub 1} were not significant at either time point after air exposure. Thus, the CO{sub 2} expirogram is useful for characterizing the effect of O{sub 3} exposure on gas transport, and for supplementing forced expired spirometry that is frequently used to quantify lung mechanics.

  1. Skin wound trauma, following high-dose radiation exposure, amplifies and prolongs skeletal tissue loss.

    PubMed

    Swift, Joshua M; Swift, Sibyl N; Smith, Joan T; Kiang, Juliann G; Allen, Matthew R

    2015-12-01

    The present study investigated the detrimental effects of non-lethal, high-dose (whole body) γ-irradiation on bone, and the impact that radiation combined with skin trauma (i.e. combined injury) has on long-term skeletal tissue health. Recovery of bone after an acute dose of radiation (RI; 8 Gy), skin wounding (15-20% of total body skin surface), or combined injury (RI+Wound; CI) was determined 3, 7, 30, and 120 days post-irradiation in female B6D2F1 mice and compared to non-irradiated mice (SHAM) at each time-point. CI mice demonstrated long-term (day 120) elevations in serum TRAP 5b (osteoclast number) and sclerostin (bone formation inhibitor), and suppression of osteocalcin levels through 30 days as compared to SHAM (p<0.05). Radiation-induced reductions in distal femur trabecular bone volume fraction and trabecular number through 120 days post-exposure were significantly greater than non-irradiated mice (p<0.05) and were exacerbated in CI mice by day 30 (p<0.05). Negative alterations in trabecular bone microarchitecture were coupled with extended reductions in cancellous bone formation rate in both RI and CI mice as compared to Sham (p<0.05). Increased osteoclast surface in CI animals was observed for 3 days after irradiation and remained elevated through 120 days (p<0.01). These results demonstrate a long-term, exacerbated response of bone to radiation when coupled with non-lethal wound trauma. Changes in cancellous bone after combined trauma were derived from extended reductions in osteoblast-driven bone formation and increases in osteoclast activity.

  2. The immune response of women with prolonged exposure to electromagnetic fields produced by radiotelevision broadcasting stations.

    PubMed

    Boscolo, P; Di Giampaolo, L; Di Donato, A; Antonucci, A; Paiardini, G; Morelli, S; Vasile, R; Spagnoli, G; Reale, M; Dadorante, V; Kouri, M; Di Gioacchino, M

    2006-01-01

    Twelve women, five of them housewives, exposed in their residences to electromagnetic fields (EMFs)emitted by radio-television broadcasting stations for a mean period of 13 years, were investigated. The EMFs in the balconies of the homes were (mean + S.D.) 4.3 + 1.4 V/m in the year 2000 and 3.7 + 1.3 V/m in 2005, while the exposure in the nearby area was <2.0 V/m. The EMF exposed women showed in 2000 reduced blood NK lymphocytes as well as PHA stimulated PBMC proliferation and IL-2 and IFN-gamma release. In the year 2005, the EMF exposed women and 48 control women with similar ages(mean 43 years), smoking habits, atopy and social level were investigated. State (temporary) and trait(tendency of the personality) anxiety were determined by STAI I and II, respectively. Blood cytotoxic activity and lymphocyte subsets were also determined. The ratio STAI I/STAI II of the EMF exposed group was lower than that of the control group. The blood cytotoxic activity of the exposed women was lower (p<0.01), percent of B CD45+-CD19+ lymphocytes higher and percent of CD45+-CD3+-CD8+ cells lower (p<0.05). Moreover, cytotoxic activity/CD45+-CD16+-56+ NK lymphocytes of the controls was negatively correlated with STAI I and STAI II (p<0.001). In conclusion, this study demonstrates reduced blood cytotoxic activity and increased trait anxiety in relation to state anxiety in EMF exposed women. An effect of EMFs on immune functions, in part mediated by nervous mechanisms, may be hypothesized. However, the influence of lifestyle may not be excluded.

  3. Prolonged exposure to low levels of aluminum leads to changes associated with brain aging and neurodegeneration.

    PubMed

    Bondy, Stephen C

    2014-01-01

    Aluminum is one of the most common metal elements in the earth's crust. It is not an essential element for life and has commonly been thought of as a rather inert and insoluble mineral. Therefore, it has often been regarded as not posing a significant health hazard. In consequence, aluminum-containing agents been used in many food processing steps and also in removal by flocculation of particulate organic matter from water. In recent years, acid rain has tended to mobilize aluminum-containing minerals into a more soluble form, ionic Al(3+), which has found their way into many reservoirs that constitute residential drinking water resources. As a result, the human body burden of aluminum has increased. Epidemiological studies suggest that aluminum may not be as innocuous as was previously thought and that aluminum may actively promote the onset and progression of Alzheimer's disease. Epidemiological data is strengthened by experimental evidence of aluminum exposure leading to excess inflammatory activity within the brain. Such apparently irrelevant immune activity unprovoked by an exogenous infectious agent characterizes the aging brain and is even more pronounced in several neurodegenerative diseases. The causation of most of these age-related neurological disorders is not understood but since they are generally not genetic, one must assume that their development is underlain by unknown environmental factors. There is an increasing and coherent body of evidence that implicates aluminum as being one such significant factor. Evidence is outlined supporting the concept of aluminum's involvement in hastening brain aging. This acceleration would then inevitably lead to increased incidence of specific age-related neurological diseases. PMID:24189189

  4. Prolonged exposure to low levels of aluminum leads to changes associated with brain aging and neurodegeneration.

    PubMed

    Bondy, Stephen C

    2014-01-01

    Aluminum is one of the most common metal elements in the earth's crust. It is not an essential element for life and has commonly been thought of as a rather inert and insoluble mineral. Therefore, it has often been regarded as not posing a significant health hazard. In consequence, aluminum-containing agents been used in many food processing steps and also in removal by flocculation of particulate organic matter from water. In recent years, acid rain has tended to mobilize aluminum-containing minerals into a more soluble form, ionic Al(3+), which has found their way into many reservoirs that constitute residential drinking water resources. As a result, the human body burden of aluminum has increased. Epidemiological studies suggest that aluminum may not be as innocuous as was previously thought and that aluminum may actively promote the onset and progression of Alzheimer's disease. Epidemiological data is strengthened by experimental evidence of aluminum exposure leading to excess inflammatory activity within the brain. Such apparently irrelevant immune activity unprovoked by an exogenous infectious agent characterizes the aging brain and is even more pronounced in several neurodegenerative diseases. The causation of most of these age-related neurological disorders is not understood but since they are generally not genetic, one must assume that their development is underlain by unknown environmental factors. There is an increasing and coherent body of evidence that implicates aluminum as being one such significant factor. Evidence is outlined supporting the concept of aluminum's involvement in hastening brain aging. This acceleration would then inevitably lead to increased incidence of specific age-related neurological diseases.

  5. The immune response of women with prolonged exposure to electromagnetic fields produced by radiotelevision broadcasting stations.

    PubMed

    Boscolo, P; Di Giampaolo, L; Di Donato, A; Antonucci, A; Paiardini, G; Morelli, S; Vasile, R; Spagnoli, G; Reale, M; Dadorante, V; Kouri, M; Di Gioacchino, M

    2006-01-01

    Twelve women, five of them housewives, exposed in their residences to electromagnetic fields (EMFs)emitted by radio-television broadcasting stations for a mean period of 13 years, were investigated. The EMFs in the balconies of the homes were (mean + S.D.) 4.3 + 1.4 V/m in the year 2000 and 3.7 + 1.3 V/m in 2005, while the exposure in the nearby area was <2.0 V/m. The EMF exposed women showed in 2000 reduced blood NK lymphocytes as well as PHA stimulated PBMC proliferation and IL-2 and IFN-gamma release. In the year 2005, the EMF exposed women and 48 control women with similar ages(mean 43 years), smoking habits, atopy and social level were investigated. State (temporary) and trait(tendency of the personality) anxiety were determined by STAI I and II, respectively. Blood cytotoxic activity and lymphocyte subsets were also determined. The ratio STAI I/STAI II of the EMF exposed group was lower than that of the control group. The blood cytotoxic activity of the exposed women was lower (p<0.01), percent of B CD45+-CD19+ lymphocytes higher and percent of CD45+-CD3+-CD8+ cells lower (p<0.05). Moreover, cytotoxic activity/CD45+-CD16+-56+ NK lymphocytes of the controls was negatively correlated with STAI I and STAI II (p<0.001). In conclusion, this study demonstrates reduced blood cytotoxic activity and increased trait anxiety in relation to state anxiety in EMF exposed women. An effect of EMFs on immune functions, in part mediated by nervous mechanisms, may be hypothesized. However, the influence of lifestyle may not be excluded. PMID:17291406

  6. Influence of body heat content on hand function during prolonged cold exposures.

    PubMed

    Flouris, A D; Cheung, S S; Fowles, J R; Kruisselbrink, L D; Westwood, D A; Carrillo, A E; Murphy, R J L

    2006-09-01

    We examined the influence of 1) prior increase [preheating (PHT)], 2) increase throughout [heating (HT)], and 3) no increase [control (Con)] of body heat content (H(b)) on neuromuscular function and manual dexterity of the hands during a 130-min exposure to -20 degrees C (coldEx). Ten volunteers randomly underwent three passive coldEx, incorporating a 10-min moderate-exercise period at the 65th min while wearing a liquid conditioning garment (LCG) and military arctic clothing. In PHT, 50 degrees C water was circulated in the LCG before coldEx until core temperature was increased by 0.5 degrees C. In HT, participants regulated the inlet LCG water temperature throughout coldEx to subjective comfort, while the LCG was not operating in Con. Thermal comfort, rectal temperature, mean skin temperature, mean finger temperature (T(fing)), change in H(b) (DeltaH(b)), rate of body heat storage, Purdue pegboard test, finger tapping, handgrip, maximum voluntary contraction, and evoked twitch force of the first dorsal interosseus muscle were recorded. Results demonstrated that, unlike in HT and PHT, thermal comfort, rectal temperature, mean skin temperature, twitch force, maximum voluntary contraction, and finger tapping declined significantly in Con. In contrast, T(fing) and Purdue pegboard test remained constant only in HT. Generalized estimating equations demonstrated that DeltaH(b) and T(fing) were associated over time with hand function, whereas no significant association was detected for rate of body heat storage. It is concluded that increasing H(b) not only throughout but also before a coldEx is effective in maintaining hand function. In addition, we found that the best indicator of hand function is DeltaH(b) followed by T(fing).

  7. Repeated Ozone Exposure Exacerbates Insulin Resistance And Activates Innate Immune Response In Genetically Susceptible Mice

    PubMed Central

    Zhong, Jixin; Allen, Katryn; Rao, Xiaoquan; Ying, Zhekang; Braunstein, Zachary; Kankanala, Saumya R.; Xia, Chang; Wang, Xiaoke; Bramble, Lori A.; Wagner, James G.; Lewandowski, Ryan; Sun, Qinghua; Harkema, Jack R.; Rajagopalan, Sanjay

    2016-01-01

    Background Inhaled ozone (O3) has been demonstrated as a harmful pollutant and associated with chronic inflammatory diseases such as diabetes and vascular disorders. However, the underlying mechanisms by which O3 mediates harmful effects are poorly understood. Objectives To investigate the effect of O3 exposure on glucose intolerance, immune activation and underlying mechanisms in a genetically susceptible mouse model. Methods Diabetes-prone KK mice were exposed to filtered air (FA), or O3 (0.5 ppm) for 13 consecutive weekdays (4 h/day). Insulin tolerance test (ITT) was performed following the last exposure. Plasma insulin, adiponectin, and leptin were measured by ELISA. Pathologic changes were examined by H&E and oil-red-o staining. Inflammatory responses were detected using flow cytometry and real-time PCR. Results KK mice exposed to O3 displayed an impaired insulin response. Plasma insulin and leptin levels were reduced in O3-exposed mice. Three-week exposure to O3 induced lung inflammation and increased monocytes/macrophages in both blood and visceral adipose tissue. Inflammatory monocytes/macrophages increased both systemically and locally. CD4+ T cell activation was also enhanced by the exposure of O3 although the relative percentage of CD4+ T cell decreased in blood and adipose tissue. Multiple inflammatory genes including CXCL-11, IFN-γ, TNFα, IL-12, and iNOS were up-regulated in visceral adipose tissue. Furthermore, the expression of oxidative stress-related genes such as Cox4, Cox5a, Scd1, Nrf1, and Nrf2, increased in visceral adipose tissue of O3-exposed mice. Conclusions Repeated O3 inhalation induces oxidative stress, adipose inflammation and insulin resistance. PMID:27240593

  8. Susceptibility to ozone-induced inflammation. I. Genetic control of the response to subacute exposure

    SciTech Connect

    Kleeberger, S.R.; Levitt, R.C.; Zhang, L.Y. )

    1993-01-01

    We demonstrated previously that C57BL/6J (B6) inbred mice are susceptible and C3H/HeJ (C3) mice are resistant to airway inflammation that is induced by acute (3 h) exposure to 2 parts per million (ppm) ozone (O3). In the present study we tested the hypothesis that B6 and C3 mice are also differentially susceptible to the airway inflammatory responses to subacute (72 h) exposure to environmentally relevant concentrations of O3 (0.12 and 0.30 ppm). Male mice (20-25 g, 5-7 wk) were exposed continuously to 0.12 ppm O3, 0.30 ppm O3, or filtered air (control). Pulmonary inflammation was assessed after 24, 48, and 72 h by differential cell count and total protein in bronchoalveolar lavage (BAL) returns. Exposure to 0.12 ppm O3 caused significant influx of alveolar macrophages, polymorphonuclear leukocytes (PMNs), lymphocytes, and total BAL protein in both strains, but no differences in the magnitude of the responses were found between B6 and C3 mice. In contrast to the effect of 0.12 ppm O3, exposure to 0.30 ppm O3 elicited significantly greater numbers of inflammatory cells and BAL protein concentration in B6 mice relative to C3 mice. The phenotypes of the B6 and C3 mice were termed susceptible and resistant, respectively. To further evaluate the potential genetic contribution to the inflammatory response to 0.30 ppm O3, the F1, F2, and backcross progeny from B6 and C3 progenitors were examined. The ratios of susceptible and resistant phenotypes of these progeny support the hypothesis that a single autosomal recessive gene confers susceptibility to subacute O3-induced inflammation.

  9. Role of Concentration and Time of Day in Developing Ozone Exposure Indices for a Secondary Standard.

    PubMed

    Lee, E H; Hogsett, W E

    1999-06-01

    Evidence from exposure-response studies and a turbulent transfer model demonstrate that plant response is differential to concentration, duration, temporal pattern, and time of day of exposure. Reductions in productivity of crops and trees as seedlings are greater when plants are exposed to higher daytime ozone (O3) concentrations (0800-2000 hr standard time) or for longer durations. Primary evidence on the greater role of concentration comes from exposure-response experiments where plants are exposed to a series of pollutant concentrations in open-top chambers under field conditions. These studies demonstrate that the integrated exposure indices that give preferential weight to higher concentrations are better predictors of response than mean or peak indices. Evidence suggesting that mid-range O3 concentrations (0.05-0.09 parts per million, ppm) play a greater role than higher concentrations (>0.09 ppm) in biological response could not be justified. The time of day when O3 concentrations and atmospheric and stomatal conductances of gas exchange are optimal is a key to understanding plant response because plants respond only to O3 entering the leaf via stomata. A turbulent transfer model that describes the resistance of pollutant gas exchange from the atmosphere to the boundary layer of a forest canopy, as a function of micrometeorological variables, is developed to determine when flux of O3 is optimal. Based on meteorological and ambient air quality monitoring data at remote forest sites in the United States, it appears that O3 flux densities to the forest boundary layer are optimal during the 0800-2000 hr window. It is concluded that descriptors of ambient air quality for use in setting a federal standard should (1) cumulate hourly O3 concentrations, (2) give preferential weight to daytime concentrations between 0800 and 2000 hr, and (3) give preferential weight to higher O3 concentrations.

  10. Characteristics of physiological and biochemical responses of soybean cultivars to short term ozone exposures

    SciTech Connect

    Sheng, Wen; Chevone, B. )

    1990-05-01

    The differential sensitivity to ozone based on the degree of visible injury among soybean (Glycine max (L.) Merr.) cvs: Dare (O{sub 3}-sensitive), Williams and Essex was investigated. Gas exchange measurements using a portable Li-Cor 6200 Photosynthesis System revealed that cv Essex maintained a higher net photosynthetic rate (Pn) than cvs Williams and Dare during a 4 hr fumigation with 0.2 {mu}l l{sup {minus}1} O{sub 3}. However, cv Dare had a higher stomatal conductance (Cs) than the other cvs during the exposure period suggesting a higher O{sub 3} influx into the leaf tissues. The maximum reductions in Pn and Cs of all cvs by O{sub 3} were approximately 30% and 70%, respectively. The antioxidant system, consisting of the metabolites: glutathione (GSH and GSSG) and ascorbic acid (AA and dHAA), and the enzymes: glutathione reductase (GRase), ascorbate peroxidase (APase) and superoxide dismutase (SOD), was found to be different in the endogenous levels or activities among cvs. There were no significant changes caused by O{sub 3} exposure, however, trends in metabolite concentrations and enzyme activities were evident. Most notably, O{sub 3} resulted in decreases of dHAA in cvs Dare and Williams, AA in cv Essex and GSSG in cv Williams and increases of GSSG in cv Essex, AA in cvs Dare and Williams and SOD in cv Dare.

  11. Atrophic rhinitis and other nasal lesions induced by a 1-month exposure of F344 rats to 0.25 or 0.5 ppm ozone

    SciTech Connect

    Hotchkiss, J.A.; Harkema, J.R.; Wacnik, P.W.

    1994-11-01

    Ozone, the principal oxidant pollutant of photochemical smog, is a common inhaled toxicant for metropolitan area residents. The effects of acute and chronic ozone exposure on inflammatory cell influx, hyperplasia, and secretory cell metaplasia within the surface epithelium lining rat nasal airways have previously been reported. On the other hand, there is a paucity of data describing the effects of ozone exposure on the subepithelial tissues (i.e., lamina propria and bone) of nasal turbinates. However, recently, a significant decrease in nasal turbinate bone area in rats chronically exposed (20 mo) to 1 ppm ozone was reported. The purpose of the present study was to examine the effects of a 1-mo ozone exposure on subepithelial tissue compartments of maxilloturbinates in the anterior nasal cavity of rats.

  12. Overexpression of hsp27 Rescued Neuronal Cell Death and Reduction in Life- and Health-Span in Drosophila melanogaster Against Prolonged Exposure to Dichlorvos.

    PubMed

    Pandey, Ashutosh; Saini, Sanjay; Khatoon, Rehana; Sharma, Divya; Narayan, Gopeshwar; Kar Chowdhuri, Debapratim

    2016-07-01

    Long-term exposure to dichlorvos (O,O-dimethyl-2,2-dichlorovinyl phosphate (DDVP), an organophosphate pesticide) is reported to exert neurotoxicity, i.e., generation of reactive oxygen species (ROS), oxidative damage, and neuronal cell death along with life- and health-span reduction in nontarget organisms including humans. However, studies on genetic modulation towards neuroprotection against prolonged DDVP exposure are elusive. Hsp27 (a small heat shock protein) is involved in various cellular processes and thus has attained emphasis as a therapeutic target. We aimed to examine the protective effect of hsp27 overexpression against prolonged DDVP exposure using an in vivo model Drosophila melanogaster. Flies were exposed to 15.0 ng/ml DDVP for a prolonged period to examine neuronal cell death, locomotor performance, and lifespan. After prolonged exposure, cell death, ROS level, glutathione depletion, nicotinamide adenine dinucleotide phosphate level (NADPH), glucose-6-phosphate dehydrogenase (G6PD), and thioredoxin reductase (TrxR) activities were examined in fly brain tissues at different days of age (days 10, 20, and 30). Flies with ubiquitous overexpression of hsp27 showed better resistance (improved lifespan and locomotor performance) in comparison to that targeted to motor neurons and nervous system. These flies also exhibited lesser intracellular ROS level and glutathione depletion by restoring G6PD activity, NADPH level, and TrxR activity in their brains thereby resisted neuronal cell death. Conversely, hsp27 knockdown flies exhibited reversal of the above endpoints. The study evidenced the neuroprotective efficacy of hsp27 overexpression against prolonged DDVP exposure and favored Hsp27 as a therapeutic target towards achieving better organismal (including human) health against long-term chemical exposure.

  13. Repeated subacute ozone exposure of inbred mice: Airway inflammation and ventilation

    SciTech Connect

    Paquette, N.C.; Tankersley, C.G.; Zhang, L.Y.

    1994-11-01

    The present study was designed to assess the effects of repeated subacute ozone (O{sub 3}) exposure on pulmonary inflammation and ventilation in two inbred strains of mice differentially susceptible to a single O{sub 3} exposure. Susceptible C57BL/6J(B6) and resistant C3H/HeJ (C3) mice were exposed to 0.3 ppm O{sub 3} for 48 and 72 h and, after 14 days recovery, both strains were reexposed. Airway inflammation and lung injury were assessed by counting inflammatory cells and measuring total protein content and lactate dehydrogenase (LDH) activity in bronchoalveolar lavage (BAL) returns. Minute ventilation [V{sub E,} the product of breathing frequency (f), and tidal volume (V{sub T})] was measured prior to and immediately following each exposure. After the initial exposure, B6 mice developed greater O{sub 3}-induced increases in total protein, inflammatory cell influx, and LDH activity compared to C3 mice. In normal air, V{sub E} was also significantly elevated in B6, but not C3, mice after O{sub 3}. The hypercapnic f of B6 and hypercapnic V{sub T} of C3 mice were significantly altered after O{sub 3} exposure. Reexposure to O{sub 3} caused a smaller increase in the numbers of macrophages, lymphocytes, epithelial cells, and BAL protein in both strains, and no changes in LDH activity. However, the number of polymorphonuclear leukocytes significantly increased in B6 and C3 mice as compared to the initial O{sub 3} exposure. In both strains, the ventilatory responses to normal air or hypercapnia were largely reproducible after O{sub 3} reexposure. Results indicated that differential susceptibility to O{sub 3}-induced inflammation was maintained in B6 and C3 mice with O{sub 3} reexposure although the magnitude of the difference was reduced. Results also suggest that the ventilatory responses to O{sub 3} in B6 and C3 mice were reproducible with reexposure, and that airway inflammation and ventilation were not codependent. 34 refs., 4 figs., 1 tab.

  14. Sensory Neural Responses to Ozone Exposure during Early Postnatal Development in Rat Airways

    PubMed Central

    Hunter, Dawn D.; Wu, Zhongxin; Dey, Richard D.

    2010-01-01

    Airway infections or irritant exposures during early postnatal periods may contribute to the onset of childhood asthma. The purpose of this study was to examine critical periods of postnatal airway development during which ozone (O3) exposure leads to heightened neural responses. Rats were exposed to O3 (2 ppm) or filtered air for 1 hour on specific postnatal days (PDs) between PD1 and PD29, and killed 24 hours after exposure. In a second experiment, rats were exposed to O3 on PD2–PD6, inside a proposed critical period of development, or on PD19–PD23, outside the critical period. Both groups were re-exposed to O3 on PD28, and killed 24 hours later. Airways were removed, fixed, and prepared for substance P (SP) immunocytochemistry. SP nerve fiber density (NFD) in control extrapulmonary (EXP) epithelium/lamina propria (EPLP) increased threefold, from 1% to 3.3% from PD1–PD3 through PD13–PD15, and maintained through PD29. Upon O3 exposure, SP-NFD in EXP–smooth muscle (SM) and intrapulmonary (INT)-SM increased at least twofold at PD1–PD3 through PD13–PD15 in comparison to air exposure. No change was observed at PD21–PD22 or PD28–PD29. In critical period studies, SP-NFD in the INT-SM and EXP-SM of the PD2–PD6 O3 group re-exposed to O3 on PD28 was significantly higher than that of the group exposed at PD19–PD23 and re-exposed at PD28. These findings suggest that O3-mediated changes in sensory innervation of SM are more responsive during earlier postnatal development. Enhanced responsiveness of airway sensory nerves may be a contributing mechanism of increased susceptibility to environmental exposures observed in human infants and children. PMID:20118220

  15. Pulmonary Function Response to Exposure to Low Concentration Ozone in Young Adults: Inter-comparison among Studies and Meta-Analysis

    EPA Science Inventory

    Rationale: It is well established that moderate ozone exposures induce decrements in spirometry volume and respiratory symptoms in healthy young adults. However, studies for low concentration ozone near the current NAAQS standard (0.070 ppm) are limited to only a few and their co...

  16. The Relationship between Posttraumatic and Depressive Symptoms during Prolonged Exposure with and without Cognitive Restructuring for the Treatment of Posttraumatic Stress Disorder

    ERIC Educational Resources Information Center

    Aderka, Idan M.; Gillihan, Seth J.; McLean, Carmen P.; Foa, Edna B.

    2013-01-01

    Objective: In the present study, we examined the relationship between posttraumatic and depressive symptoms during prolonged exposure (PE) treatment with and without cognitive restructuring (CR) for the treatment of posttraumatic stress disorder (PTSD). Method: Female assault survivors (N = 153) with PTSD were randomized to either PE alone or PE…

  17. Treating Low-Income and Minority Women with Posttraumatic Stress Disorder: A Pilot Study Comparing Prolonged Exposure and Treatment as Usual Conducted by Community Therapists

    ERIC Educational Resources Information Center

    Feske, Ulrike

    2008-01-01

    Twenty-one female psychiatric outpatients with chronic posttraumatic stress disorder (PTSD) are randomly assigned to prolonged exposure (PE; n = 9) for PTSD or treatment as usual (TAU; n = 12). Participants are predominately low income and African American with complex trauma and psychiatric histories. Treatment is delivered by community…

  18. Alteration of extracellular enzymes in pinto bean leaves upon exposure to air pollutants, ozone and sulfur dioxide

    SciTech Connect

    Peters, J.L.; Castillo, F.J.; Heath, R.L. )

    1989-01-01

    Diamine oxidase and peroxidase, associated with the wall in pinto bean (Phaseolus vulgaris L. var Pinto) leaves, can be washed out by vacuum infiltration and assayed without grinding the leaf. The diamine oxidase activity is inhibited in vivo by exposure of the plants to ozone (dose of 0.6 microliters per liter {times} hour), whereas the peroxidase activity associated with the wall space is stimulated. This dose does not cause obvious necrosis or chlorosis of the leaf. These alterations are greater when the dose of ozone exposure is given as a triangular pulse (a slow rise to a peak of 0.24 microliters per liter followed by a slow fall) compared to that given as a constant square wave pulse of 0.15 microliters per liter for the same 4 hour period. Exposure of the plants to sulfur dioxide (at a concentration of 0.4 microliters per liter for 4 hours) does not result in any change in the diamine oxidase or peroxidase activities, yet the total sulfhydryl content of the leaf is increased, demonstrating the entry of sulfur dioxide. These two pollutants, with different chemical reactivities, affect the activities of the extracellular enzymes in different manners. In the case of ozone exposure, the inhibition of extracellular diamine oxidase could profoundly alter the movements of polyamines from cell to cell.

  19. Air pollution and childhood respiratory health: Exposure to sulfate and ozone in 10 Canadian Rural Communities

    SciTech Connect

    Stern, B.R.; Raizenne, M.E.; Burnett, R.T.; Jones, L.; Kearney, J.; Franklin, C.A. )

    1994-08-01

    This study was designed to examine differences in the respiratory health status of preadolescent school children, aged 7-11 years, who resided in 10 rural Canadian communities in areas of moderate and low exposure to regional sulfate and ozone pollution. Five of the communities were located in central Saskatchewan, a low-exposure region, and five were located in southwestern Ontario, an area with moderately elevated exposures resulting from long-range atmospheric transport of polluted air masses. In this cross-sectional study, the child's respiratory symptoms and illness history were evaluated using a parent-completed questionnaire, administered in September 1985. Respiratory function was assessed once for each child in the schools between October 1985 and March 1986, by the measurement of pulmonary function for forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV[sub 1.0]), peak expiratory flow rate (PEFR), mean forced expiratory flow rate during the middle half of the FVC curve (FEF[sub 25-75]), and maximal expiratory flow at 50% of the expired vital capacity (V[sub 50]max). After controlling for the effects of age, sex, parental smoking, parental education and gas cooking, no significant regional differences were observed in rates of chronic cough or phlegm, persistent wheeze, current asthma, bronchitis in the past year, or any chest illness that kept the child at home for 3 or more consecutive days during the previous year. Children living in southwestern Ontario had statistically significant (P < 0.01) mean decrements of 1.7% in FVC and 1.3% in FEV[sub 1.0] compared with Saskatchewan children, after adjusting for age, sex, weight, standing height, parental smoking, and gas cooking. There were no statistically significant regional differences in the pulmonary flow parameters (P > 0.05). 54 refs., 1 fig., 7 tabs.

  20. Estimated crop yield losses due to surface ozone exposure and economic damage in India.

    PubMed

    Debaje, S B

    2014-06-01

    In this study, we estimate yield losses and economic damage of two major crops (winter wheat and rabi rice) due to surface ozone (O3) exposure using hourly O3 concentrations for the period 2002-2007 in India. This study estimates crop yield losses according to two indices of O3 exposure: 7-h seasonal daytime (0900-1600 hours) mean measured O3 concentration (M7) and AOT40 (accumulation exposure of O3 concentration over a threshold of 40 parts per billion by volume during daylight hours (0700-1800 hours), established by field studies. Our results indicate that relative yield loss from 5 to 11% (6-30%) for winter wheat and 3-6% (9-16%) for rabi rice using M7 (AOT40) index of the mean total winter wheat 81 million metric tons (Mt) and rabi rice 12 Mt production per year for the period 2002-2007. The estimated mean crop production loss (CPL) for winter wheat are from 9 to 29 Mt, account for economic cost loss was from 1,222 to 4,091 million US$ annually. Similarly, the mean CPL for rabi rice are from 0.64 to 2.1 Mt, worth 86-276 million US$. Our calculated winter wheat and rabi rice losses agree well with previous results, providing the further evidence that large crop yield losses occurring in India due to current O3 concentration and further elevated O3 concentration in future may pose threat to food security.

  1. Inflammatory Cytokines and White Blood Cell Counts Response to Environmental Levels of Diesel Exhaust and Ozone Inhalation Exposures

    PubMed Central

    Stiegel, Matthew A.; Pleil, Joachim D.; Sobus, Jon R.; Madden, Michael C.

    2016-01-01

    Epidemiological observations of urban inhalation exposures to diesel exhaust (DE) and ozone (O3) have shown pre-clinical cardiopulmonary responses in humans. Identifying the key biological mechanisms that initiate these health bioindicators is difficult due to variability in environmental exposure in time and from person to person. Previously, environmentally controlled human exposure chambers have been used to study DE and O3 dose-response patterns separately, but investigation of co-exposures has not been performed under controlled conditions. Because a mixture is a more realistic exposure scenario for the general public, in this study we investigate the relationships of urban levels of urban-level DE exposure (300 μg/m3), O3 (0.3 ppm), DE + O3 co-exposure, and innate immune system responses. Fifteen healthy human volunteers were studied for changes in ten inflammatory cytokines (interleukins 1β, 2, 4, 5, 8, 10, 12p70 and 13, IFN-γ, and TNF-α) and counts of three white blood cell types (lymphocytes, monocytes, and neutrophils) following controlled exposures to DE, O3, and DE+O3. The results show subtle cytokines responses to the diesel-only and ozone-only exposures, and that a more complex (possibly synergistic) relationship exists in the combination of these two exposures with suppression of IL-5, IL-12p70, IFN-γ, and TNF-α that persists up to 22-hours for IFN-γ and TNF-α. The white blood cell differential counts showed significant monocyte and lymphocyte decreases and neutrophil increases following the DE + O3 exposure; lymphocytes and neutrophils changes also persist for at least 22-hours. Because human studies must be conducted under strict safety protocols at environmental levels, these effects are subtle and are generally only seen with detailed statistical analysis. This study indicates that the observed associations between environmental exposures and cardiopulmonary effects are possibly mediated by inflammatory response mechanisms. PMID:27058360

  2. An in vitro system for exposure of lung cells to gases: effects of ozone on rat macrophages.

    PubMed

    Valentine, R

    1985-01-01

    A test system was developed for the in vitro exposure of lung cells to gases. The exposure system was used to evaluate ozone (O3) injury to pulmonary alveolar macrophages (PAM) obtained from Sprague-Dawley rats by bronchopulmonary lavage. Ozone exposures were conducted within temperature-controlled stainless-steel and Plexiglas chambers that contained glass petri dishes affixed to a revolving, inclined platform. Cell exposures were accomplished by rotation of the platform at 1 rpm to alternately expose PAM monolayers to culture media and O3. The system provided stable, O3-containing atmospheres and permitted simultaneous in vitro exposures at three O3 concentrations. In vitro exposure of PAM monolayers for 2 h at chamber concentrations ranging from 0.2 to 6.1 ppm O3 was associated with a significant, concentration-related reduction of latex-bead phagocytosis in rotated PAM cultures. In contrast, PAM that were similarly exposed in nonrotated dishes placed horizontally and covered with a stationary layer of media (1.5 mm depth) were not affected. Other parameters of cell function, including PAM viability and adherence, were unchanged compared to unexposed or horizontal, nonrotated controls. The inability to observe adverse effects among the nonrotated cultures is consistent with the impaired diffusion of O3 through the comparatively thick media overlay in stationary cultures. The in vitro system provides a realistic simulation of lung cell exposure to O3 and represents a useful model to study the toxicity of gases on cultured cells.

  3. Are 60-minute prolonged exposure sessions with 20-minute imaginal exposure to traumatic memories sufficient to successfully treat PTSD? A randomized noninferiority clinical trial.

    PubMed

    Nacasch, Nitsa; Huppert, Jonathan D; Su, Yi-Jen; Kivity, Yogev; Dinshtein, Yula; Yeh, Rebecca; Foa, Edna B

    2015-05-01

    The study aims to determine whether 60-minute sessions of prolonged exposure (PE) that include 20 minutes of imaginal exposure (IE) are noninferior to the standard 90-minute sessions that include 40 minutes of IE in treating posttraumatic stress disorder (PTSD) and to explore the relationship of treatment outcome to within- and between-session habituation and change in negative cognitions. Thirty-nine adult veterans with chronic PTSD were randomly assigned to 90-minute (n=19) or 60-minute (n=20) sessions of PE. PTSD symptoms were assessed by an unaware independent evaluator before and after treatment and at 6-month follow-up. Self-reports of depression and negative cognitions were assessed before and after treatment. Participants in both conditions showed significant reductions in PTSD symptoms. Sixty-minute sessions were found to be noninferior to 90-minute sessions in reducing PTSD symptoms, as the upper bound of the 95% confidence interval for the difference between conditions in the PTSD Symptom Scale-Interview (posttreatment: 6.00; follow-up: 6.77) was below the predefined noninferiority margin (7.00). Participants receiving shorter sessions showed less within- and between-session habituation than those receiving longer sessions, but no group differences in reductions in negative cognitions were found. The current findings indicate that the outcomes of 60-minute sessions of PE do not differ from those of 90-minute sessions. In addition, change in trauma-related cognitions and between-session habituation are both potential mechanisms of PE.

  4. Prolonged ELS test with the marine flatfish sole (Solea solea) shows delayed toxic effects of previous exposure to PCB 126.

    PubMed

    Foekema, Edwin M; Deerenberg, Charlotte M; Murk, Albertinka J

    2008-11-21

    The effect of the dioxin-like PCB 126 (3,3',4,4',5-pentachlorobiphenyl) on the early development of the marine flatfish sole (Solea solea) was tested in a newly developed early life stage (ELS) test that includes the metamorphosis of the symmetric larvae into an asymmetrical flatfish. Early life stages of sole were exposed to a concentration series of PCB 126 in seawater until 4, 8, 10 and 15 days post fertilisation (dpf). Subsequently the development of the larvae was registered under further unexposed conditions. The LC50s at the start of the free-feeding stage (12 dpf) ranged between 39 and 83 ng PCB 126/l depending on exposure duration. After the fish had completed the metamorphosis, the LC50 values ranged between 1.7 and 3.7 ng PCB 126/l for the groups exposed for 4, 8 and 10 dpf, respectively. Thus exposure for only 4 days, covering only the egg stage, was sufficient to cause adverse effects during a critical developmental phase two weeks later. The internal dosages of these larvae, determined by means of an in vitro gene reporter assay as dioxin-equivalent values (TEQ), revealed a LD50 of 1ng TEQ/g lipid, which is within the same order of magnitude as TEQ levels found in fish from highly polluted areas. This study indicates that ELS fish tests that are terminated shortly after the fish becomes free-feeding, underestimate the toxic potential of compounds with low acute toxicity such as PCBs. Our prolonged ELS with this native marine flatfish suggests that reproductive success of fish populations at contaminated sites can be affected by persistent compounds that are accumulated by the female fish and passed on to the eggs.

  5. Exposure to a Mixture of Polychlorinated Biphenyls and Polychlorinated Dibenzofurans Resulted in a Prolonged Time to Pregnancy in Women

    PubMed Central

    Yang, Chiu-Yueh; Wang, Ying-Jan; Chen, Pau-Chung; Tsai, Shaw-Jenq; Guo, Yueliang Leon

    2008-01-01

    Background Polychlorinated biphenyls (PCBs), dibenzofurans (PCDFs), and dibenzodioxins (PCDDs) may affect the female reproductive system in animals and humans. In 1978–1979, a mass poisoning occurred in central Taiwan due to PCB/PCDF-contaminated cooking oil; this incident was called Yucheng (“oil disease” in Chinese). Objective The purpose of our study was to determine whether PCB/PCDF exposure affected fertility in exposed women. Methods After the event, we followed the exposed individuals and a reference group who were sex-, age-, and community-matched. In 2003, we obtained fertility histories from Yucheng and reference women by telephone interview. We used Kaplan–Meier survival curves and multivariable Cox regression to compare time to pregnancy (TTP) between Yucheng and reference women, and we performed multiple logistic regression to determine whether PCB/PCDF exposure caused infertility. Results In total, 412 women responded, with a median TTP of 4 months in Yucheng women and 3 months in reference women (p = 0.019). After adjusting for confounders by Cox regression, we found a fecundability ratio of 0.90 [95% confidence interval (CI), 0.80–1.00] for Yucheng women. Among the 408 women who had noncontraceptive sexual activity for > 12 months, 19.7% of Yucheng women and 9.7% of reference women did not become pregnant (i.e., they were infertile). After we adjusted for confounders by logistic regression, the infertility odds ratio was 2.34 (95% CI, 1.23–4.59) for Yucheng women compared with the reference group. Conclusions We found prolonged TTP and reduced fertility among women previously exposed to PCBs/PCDFs. Because of the limited sample size and the relatively small decrease in the fertility rate, these effects require cautious interpretation and further investigation for confirmation. PMID:18470317

  6. Static torsional otolith-cervical-ocular reflex after prolonged exposure to weightlessness and a 7-day immersion

    NASA Astrophysics Data System (ADS)

    Kornilova, L. N.; Naumov, I. A.; Makarova, S. M.

    2011-05-01

    To determine the role of the support-proprioceptive factor in the functioning of the vestibular system, in particular the static torsional otolith-cervical-ocular reflex (OCOR), comparative OCOR studies with videooculography recording were performed after a 7-day "dry" horizontal immersion (16 subjects) and after a prolonged (126-195 days) exposure to weightlessness (13 cosmonauts). For the first time, it was demonstrated that minimization of the support and proprioceptive afferentation may result in an inversion or absence of the static torsional OCOR and the development of a positional nystagmus with an inverted reflex. A comparative OCOR data analysis of cosmonauts and immersion subjects has revealed similarity of responses. However, changes in OCOR after immersion were noted in only 60% of the subjects, while after space flight, 90% of cosmonauts showed them. Post-flight changes were more frequent, marked and long-lasting. Statistical analysis has shown that there were significant differences between pre- and post-flight data according to both parametric and non-parametric methods of multiple comparisons, whereas only parametric methods have found significant differences within immersion data.

  7. Changes in Negative Cognitions Mediate PTSD Symptom Reductions During Client-Centered Therapy and Prolonged Exposure for Adolescents

    PubMed Central

    McLean, Carmen P.; Yeh, Rebecca; Rosenfield, David; Foa, Edna B.

    2015-01-01

    Objective To assess whether changes in negative trauma-related cognitions play an important role in reducing symptoms of posttraumatic stress disorder (PTSD) and depression during prolonged exposure therapy for adolescents (PE-A). Method Secondary analysis of data from a randomized controlled trial comparing PE-A with client-centered therapy (CCT) for PTSD. Participants were 61 adolescent female sexual assault survivors ages 13–18 who received 8–14 weekly sessions of PE-A or CCT at a community rape crisis center. PTSD severity was assessed at baseline, mid-treatment, post-treatment, and 3-months post-treatment. Participants also completed self-report measures of negative posttraumatic cognitions and depressive symptoms at the same assessment points. Results Cross lag panel mediation analyses showed that change in negative trauma-related cognitions mediated change in PTSD symptoms and depressive symptoms whereas change in PTSD and depressive symptoms did not mediate change in negative cognitions. Conclusion Our findings support EPT and suggest that change in negative trauma-related cognitions is a mechanism of both PE-A and CCT. PMID:25812826

  8. Prolonged Exposure for Treating PTSD Among Female Methadone Patients Who Were Survivors of Sexual Abuse in Israel.

    PubMed

    Schiff, Miriam; Nacasch, Nitsa; Levit, Shabtay; Katz, Noam; Foa, Edna B

    2015-01-01

    The aims of this pilot study were: (a) to test the feasibility of prolonged exposure (PE) therapy conducted by a social worker staff on female patients in methadone program clinics who were survivors of child sexual abuse or rape and (b) to examine preliminary outcomes of PE on posttraumatic stress disorder (PTSD), depression, and illicit drug use at pre- and posttreatment, and up to 12-month follow-ups. Twelve female methadone patients who were survivors of child sexual abuse or rape diagnosed with PTSD were enrolled in 13-19 weekly individual PE sessions. Assessments were conducted at pre-, mid-, and posttreatment, as well as at 3, 6, and 12-month follow-ups. The treatment outcomes measures included PTSD symptoms, depressive symptoms, and illicit drug use. Ten of the 12 study patients completed treatment. PTSD and depressive symptoms showed significant reduction. No relapse to illicit drug use was detected. These preliminary results suggest that PE may be delivered by methadone social workers with successful outcomes. Further research should test the efficacy of PE among methadone patients in a randomized control trial with standard care as the control condition.

  9. Imagery rescripting and reprocessing therapy after failed prolonged exposure for post-traumatic stress disorder following industrial injury.

    PubMed

    Grunert, Brad K; Weis, Jo M; Smucker, Mervin R; Christianson, Heidi F

    2007-12-01

    Prolonged exposure (PE) has been reported to be effective for improving post-traumatic stress symptoms in 60-65% of trauma victims suffering from post-traumatic stress disorder (PTSD). This study examined the results of adding an imagery-based, cognitive restructuring component (imagery rescripting and reprocessing therapy, IRRT) to the treatment of 23 Type I trauma victims suffering from PTSD, all of whom failed to improve with PE alone. With the added treatment component, 18 of 23 clients showed a full recovery from their PTSD symptoms, and no longer met criteria for PTSD after 1-3 sessions of IRRT. It was noteworthy that non-FEAR emotions (e.g., guilt, shame, anger) were found to be predominant for all 23 PE failures examined in this study, suggesting that a simple habituation model (on which PE is based) is not sufficient to address non-FEAR emotions in PTSD. By contrast, IRRT, a cognitive restructuring treatment, was much more effective in PTSD symptom reduction for these clients. It was proposed that more detailed, individualized trauma assessments be conducted for each patient that focus on (1) identifying the predominant trauma-related emotions and cognitions that maintain the PTSD response, and (2) finding the best CBT "treatment fit" for the specific trauma characteristics of each patient.

  10. Effects of acute ozone exposure on the electrophysiological properties of guinea pig trachea

    SciTech Connect

    Croxton, T.L.; Takahashi, Masahiko; Kokia, Ira

    1994-12-31

    Acute ozone (O{sub 3}) exposures produce an increase in the apparent permeability of the tracheal epithelium, but the mechanism of this response is poorly understood. Comparison of previous studies suggests that qualitative differences may exist between measurements made in vivo or in vitro. To test this possibility we used both in vitro and in vivo electrophysiological techniques to investigate the effects of O{sub 3} exposure on guinea pig tracheal epithelium. Male Hartley guinea pigs were exposed to either 1 or 2 ppm O{sub 3} or to filtered air for 3 h and were studied 0, 6, or 24 h after exposure. Air-exposed animals had in vitro mean tracheal potential (V{sub T}) -32.0 {+-} 1.5 mV, conductance (G{sub T}{sup L}) 2.18 {+-} 0.22 mS/cm, short-circuit current (I{sub SC}{sup L}) 62.6 {+-} 3.7 {mu}A/cm, and diameter (D) 2.44 {+-} 0.10 mm. In vitro properties after 1 ppm O{sub 3} exposure did not differ at any time point from control. Two parts per million O{sub 3} increased I{sub SC}{sup L}, but only at 6 h postexposure. The effect of O{sub 3} on I{sub SC}{sup L} was abolished by amiloride. There were no significant changes in V{sub T}, G{sub T}{sup L}, or D. In vivo tracheal potential under pentobarbital anesthesia was -19.7 {+-} 1.7 mV. At 6 h postexposure to 2 ppm O{sub 3}, but not at 0 or 24 h, in vivo V{sub I} was increased. Thus, acute exposure of guinea pigs to a high concentration of O{sub 3} caused a delayed increase in Na{sup +} absorption by the trachea with no change in conductance. This indicates that paracellular permeability of guinea pig tracheal epithelium was not substantially increased by acute O{sub 3} and suggests that enhanced macromolecular uptake in this species probably occurs transcellularly. 24 refs., 1 fig., 2 tabs.

  11. The effects of prolonged thermal exposure on the fracture and fatigue behavior of aluminum-lithium alloy 8090

    SciTech Connect

    Venkateswara Rao, K.T.; Ritchie, R.O. ); McNulty, J.C. . Materials Dept.)

    1993-10-01

    Aluminum-lithium alloys are currently being considered for applications at moderately elevated temperatures; accordingly, a study has been made on the effects of prolonged (100 and 1,000 hours overaging) thermal exposure at 149 C and 260 C on the mechanical properties of a peak-aged Al-Li-Cu-Mg-Zr alloy 8090-T8771. In the as-received T8771 temper, the alloy exhibits an excellent combination of strength ([approximately]500 MPa) and toughness (35 MPa[radical]m) with moderate tensile elongation (4 pct). Overaging at 149 C results in a [approximately]50 pct reduction in ductility and toughness, primarily associated with the growth of equilibrium phases along grain/subgrain boundaries, resulting in formation of solute-depleted precipitate-free zones and coarsening of matrix [delta][prime] and S precipitates; strength levels and fatigue-crack growth rates, however, remain largely unchanged. Thermal exposures at 260 C, conversely, lead to dramatic reductions in strength (by [approximately]50 to 80 pct), toughness (by [approximately]30 pct) and fatigue-crack propagation resistance; crack-growth rates at all [Delta]K levels above [approximately]5 MPa[radical]m are 2 to 3 orders of magnitude faster. Microstructurally, this was associated with complete dissolution of [delta][prime], severe coarsening of S and T[sub 2] precipitates in the matrix, and formation of equilibrium Cu and Mg-rich intermetallic phases in the matrix and along grain boundaries. The resulting lack of planar-slip deformation and low yield strength of 8090 following overaging exposures at 260 C increase the cumulative crack-tip damage per cycle and reduce the tendency for crack-path deflection, thereby accelerating fatigue-crack growth rates. Despite this degradation in properties, the 8090-T8771 alloy has better strength retention and generally superior fatigue-crack growth properties compared to similarly overaged Al-Li-Cu-Zr 2090 and Al-Cu-Zn-Mg 7,150 alloys.

  12. Prolonged exposure to acid and bile induces chromosome abnormalities that precede malignant transformation of benign Barrett’s epithelium

    PubMed Central

    2012-01-01

    Abstract Barrett’s esophagus (BE) is an asymptomatic, pre-malignant condition of the esophagus that can progress to esophageal adenocarcinoma (EAC). BE arises typically in individuals with long-standing gastroesophageal reflux disease (GERD). The neoplastic progression of BE has been extensively studied histologically and defined as a metaplasia- dyplasia- carcinoma sequence. However the genetic basis of this process is poorly understood. It is conceived that preclinical models of BE may facilitate discovery of molecular markers due to ease of longitudinal sampling. Clinical markers to stratify the patients at higher risk are vital to institute appropriate therapeutic intervention since EAC has very poor prognosis. We developed a dynamic in-vitro BE carcinogenesis (BEC) model by exposing naïve Barrett’s epithelium cell line (BAR-T) to acid and bile at pH4 (B4), 5min/day for a year. The BEC model acquired malignant characteristics after chronic repeated exposure to B4 similar to the sequential progression of BE to EAC in vivo. Aim To study cytogenetic changes during progressive transformation in the BEC model. Results We observed that the BAR-T cells progressively acquired several chromosomal abnormalities in the BEC model. Evidence of chromosomal loss (-Y) rearrangements [t(10;16) and dup (11q)] and clonal selection appeared during the early stages of the BEC model. Clonal selection resulted in a stabilized monoclonal population of cells that had a changed morphology and formed colony in soft agar. BAR-T cells grown in parallel without any exposure did not show any of these abnormalities. Conclusions Prolonged acid and bile exposure induced chromosomal aberrations and clonal selection in benign BAR-T cells. Since aneuploidy preceded morphological/dysplastic changes in the BEC model, chromosomal aberrations may be an early predictor of BE progression. The [t(10;16) and dup(11q)] aberrations identified in this study harbor several genes associated with cancer

  13. Protein Cross-Linking and Oligomerization through Dityrosine Formation upon Exposure to Ozone.

    PubMed

    Kampf, Christopher J; Liu, Fobang; Reinmuth-Selzle, Kathrin; Berkemeier, Thomas; Meusel, Hannah; Shiraiwa, Manabu; Pöschl, Ulrich

    2015-09-15

    Air pollution is a potential driver for the increasing prevalence of allergic disease, and post-translational modification by air pollutants can enhance the allergenic potential of proteins. Here, the kinetics and mechanism of protein oligomerization upon ozone (O3) exposure were studied in coated-wall flow tube experiments at environmentally relevant O3 concentrations, relative humidities and protein phase states (amorphous solid, semisolid, and liquid). We observed the formation of protein dimers, trimers, and higher oligomers, and attribute the cross-linking to the formation of covalent intermolecular dityrosine species. The oligomerization proceeds fast on the surface of protein films. In the bulk material, reaction rates are limited by diffusion depending on phase state and humidity. From the experimental data, we derive a chemical mechanism and rate equations for a kinetic multilayer model of surface and bulk reaction enabling the prediction of oligomer formation. Increasing levels of tropospheric O3 in the Anthropocene may promote the formation of protein oligomers with enhanced allergenicity and may thus contribute to the increasing prevalence of allergies. PMID:26287571

  14. The effects of sequential exposure to acidic fog and ozone on pulmonary function in exercising subjects

    SciTech Connect

    Aris, R.; Christian, D.; Sheppard, D.; Balmes, J.R. )

    1991-01-01

    In Southern California coastal regions, morning fog is often acidified by the presence of nitric acid (HNO{sub 3}). Peak exposure to ozone (O{sub 3}) usually occurs in the afternoon and evening, after the fog has dissipated. To determine whether fog containing HNO{sub 3} might enhance pulmonary responses to O{sub 3}, we studied a group of healthy, athletic subjects selected for lung function sensitivity to O{sub 3}. On 3 separate days, the subjects exercised for 2 h in atmospheres containing HNO{sub 3} fog (0.5 mg/ml), H{sub 2}O fog, or clean, filtered air. After a 1-h break, they exercised for an additional 3 h in an atmosphere containing 0.20 ppm O{sub 3}. Surprisingly, the mean O{sub 3}-induced decrements in FEV1 and FVC were smaller after exercise in each fog-containing atmosphere than they were after exercise in clean, filtered air. The mean (+/- SEM) O{sub 3}-induced decrements in FEV1 were 26.4 +/- 5.3% after air, 17.1 +/- 3.7% after H{sub 2}O fog, and 18.0 +/- 4.3% after HNO{sub 3} fog, and in FVC they were 19.9 +/- 4.7% after air, 13.6 +/- 2.8% after H{sub 2}O fog, and 13.6 +/- 4.2% after HNO{sub 3} fog.

  15. Canopy carbon budget of Siebold's beech (Fagus crenata) sapling under free air ozone exposure.

    PubMed

    Watanabe, Makoto; Hoshika, Yasutomo; Inada, Naoki; Koike, Takayoshi

    2014-01-01

    To determine the effects of ozone (O3) on the canopy carbon budget, we investigated photosynthesis and respiration of leaves of Siebold's beech saplings under free air O3 exposure (60 nmol mol(-1), during daytime) in relation to the within-canopy light gradient; we then calculated the canopy-level photosynthetic carbon gain (PCG) and respiratory carbon loss (RCL) using a canopy photosynthesis model. Susceptibilities of photosynthesis and respiration to O3 were greater in leaves of upper canopy than in the lower canopy. The canopy net carbon gain (NCG) was reduced by O3 by 12.4% during one growing season. The increased RCL was the main factor for the O3-induced reduction in NCG in late summer, while contributions of the reduced PCG and the increased RCL to the NCG were almost the same in autumn. These results indicate contributions of changes in PCG and RCL under O3 to NCG were different between seasons.

  16. Effect of ozone exposure on the oxidation of trace organic contaminants in wastewater.

    PubMed

    Wert, Eric C; Rosario-Ortiz, Fernando L; Snyder, Shane A

    2009-03-01

    Three tertiary-treated wastewater effluents were evaluated to determine the impact of wastewater quality (i.e. effluent organic matter (EfOM), nitrite, and alkalinity) on ozone (O(3)) decomposition and subsequent removal of 31 organic contaminants including endocrine disrupting compounds, pharmaceuticals, and personal care products. The O(3) dose was normalized based upon total organic carbon (TOC) and nitrite to allow comparison between the different wastewaters with respect to O(3) decomposition. EfOM with higher molecular weight components underwent greater transformation, which corresponded to increased O(3) decomposition when compared on a TOC basis. Hydroxyl radical (()OH) exposure, measured by parachlorobenzoic acid (pCBA), showed that limited ()OH was available for contaminant destruction during the initial stage of O(3) decomposition (t<30s) due to the effect of the scavenging by the water quality. Advanced oxidation using O(3) and hydrogen peroxide did not increase the net production of ()OH compared to O(3) under the conditions studied. EfOM reactivity impacted the removal of trace contaminants when evaluated based on the O(3):TOC ratio. Trace contaminants with second order reaction rate constants with O(3)(k(O)(3))>10(5)M(-1)s(-1) and ()OH (k(OH))>10(9)M(-1)s(-1), including carbamazepine, diclofenac, naproxen, sulfamethoxazole, and triclosan, were >95% removed independent of water quality when the O(3) exposure (integralO(3)t) was measurable (0-0.8mgmin/L). O(3) exposure would be a conservative surrogate to assess the removal of trace contaminants that are fast-reacting with O(3). Removal of contaminants with k(O)(3) < 10M(-1)S(-1) , and k(OH)>10(9)M(-1)s(-1), including atrazine, iopromide, diazepam, and ibuprofen, varied when O(3) exposure could not be measured, and appeared to be dependent upon the compound specific k(OH). Atrazine, diazepam, ibuprofen and iopromide provided excellent linear correlation with pCBA (R(2)>0.86) making them good

  17. RNA-seq analysis reveals genetic response and tolerance mechanisms to ozone exposure in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxidative stress caused by ground level ozone is a major contributor to yield loss in a number of important crop plants. Soybean (Glycine max) is especially ozone sensitive, and research into its response to oxidative stress is limited. To better understand the genetic response in soybean to oxida...

  18. Ozone exposure inside museums in the historic central district of Krakow, Poland

    NASA Astrophysics Data System (ADS)

    Salmon, Lynn G.; Cass, Glen R.; Bruckman, Katarzyna; Haber, Jerzy

    Ozone present in the indoor atmosphere of museums can lead to the fading of organic artists' pigments and textile dyes that are present in paintings, tapestries and historically important clothing exhibits. Ozone concentrations were measured in outdoor air and within the interior galleries of five institutions that house cultural properties in Krakow. The purpose of these experiments was to determine the degree of penetration of outdoor ozone into these museums, and in the case of the National Museum to determine the effectiveness of the existing ozone removal system at that site. It was found that those museums that are rapidly ventilated through many open doors and windows experienced indoor ozone concentrations about 42-44% as high as those outdoors. The Senator's Hall at Wawel Castle, which houses important tapestries, experiences indoor ozone concentrations that are 17-19% of those outdoors due to ozone removal at interior surfaces during transit through the building from distant air intake points. Methods for further reduction of ozone concentrations in the specific museums studied are discussed.

  19. Changes in PTSD and Depression during Prolonged Exposure and Client-Centered Therapy for PTSD in Adolescents

    PubMed Central

    McLean, Carmen P.; Su, Yi-Jen; Carpenter, Joseph K.; Foa, Edna B.

    2015-01-01

    Objective Depressive symptoms are common among individuals with posttraumatic stress disorder (PTSD). Prolonged exposure therapy (PE) for PTSD has been found to alleviate both PTSD and depressive symptoms, but relatively little is known about the pattern of PTSD and depressive symptom change during treatment. This study aimed to investigate the relationship between changes in PTSD and depression during PE for adolescent (PE-A) and client-centered Therapy (CCT). The moderating role of PE-A vs. CCT and the possible differences across symptom clusters of PTSD were also examined. Method Participants were 61 female adolescents with sexual assault-related PTSD randomized to PE-A (n = 31) or CCT (n = 30). Participants completed the Beck Depression Inventory and the Child PTSD Symptom Scale at pre-, mid-, and post-treatment, and before each treatment session. Results Multilevel mediation analysis indicated a reciprocal but asymmetrical relationship between changes in PTSD and depression during treatment in the overall sample. Moderated mediation analysis showed that the reciprocal relation was observed only during PE-A. Reductions in PTSD led to reductions in depression to a greater extent (48.7%, 95% CI [30.2, 67.2]) than vice versa (22.0% [10.6, 33.4]). For participants receiving CCT, reduction in PTSD led to reductions in depression (31.6% [11.8, 51.4]) but not vice versa (7.4% [−7.1, 21.9]). The reciprocal relationship between PTSD and depression was also observed across different symptoms clusters of PTSD. Conclusions Our findings suggest that changes in PTSD led to changes in depressive symptoms to a greater extent than vice versa across PE-A and CCT. PMID:25751238

  20. Treating posttraumatic stress disorder with MDMA-assisted psychotherapy: A preliminary meta-analysis and comparison to prolonged exposure therapy.

    PubMed

    Amoroso, Timothy; Workman, Michael

    2016-07-01

    Since the wars in Iraq and Afghanistan, posttraumatic stress disorder (PTSD) has become a major area of research and development. The most widely accepted treatment for PTSD is prolonged exposure (PE) therapy, but for many patients it is intolerable or ineffective. ±3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy (MDMA-AP) has recently re-emerged as a new treatment option, with two clinical trials having been published and both producing promising results. However, these results have yet to be compared to existing treatments. The present paper seeks to bridge this gap in the literature. Often the statistical significance of clinical trials is overemphasized, while the magnitude of the treatment effects is overlooked. The current meta-analysis aims to provide a comparison of the cumulative effect size of the MDMA-AP studies with those of PE. Effect sizes were calculated for primary and secondary outcome measures in the MDMA-AP clinical trials and compared to those of a meta-analysis including several PE clinical trials. It was found that MDMA-AP had larger effect sizes in both clinician-observed outcomes than PE did (Hedges' g=1.17 vs. g=1.08, respectively) and patient self-report outcomes (Hedges' g=0.87 vs. g=0.77, respectively). The dropout rates of PE and MDMA-AP were also compared, revealing that MDMA-AP had a considerably lower percentage of patients dropping out than PE did. These results suggest that MDMA-AP offers a promising treatment for PTSD. PMID:27118529

  1. Ozone and allergen exposure during postnatal development alters the frequency and airway distribution of CD25+ cells in infant rhesus monkeys

    SciTech Connect

    Miller, Lisa A. Gerriets, Joan E.; Tyler, Nancy K.; Abel, Kristina; Schelegle, Edward S.; Plopper, Charles G.; Hyde, Dallas M.

    2009-04-01

    The epidemiologic link between air pollutant exposure and asthma has been supported by experimental findings, but the mechanisms are not understood. In this study, we evaluated the impact of combined ozone and house dust mite (HDM) exposure on the immunophenotype of peripheral blood and airway lymphocytes from rhesus macaque monkeys during the postnatal period of development. Starting at 30 days of age, monkeys were exposed to 11 cycles of filtered air, ozone, HDM aerosol, or ozone + HDM aerosol. Each cycle consisted of ozone delivered at 0.5 ppm for 5 days (8 h/day), followed by 9 days of filtered air; animals received HDM aerosol during the last 3 days of each ozone exposure period. Between 2-3 months of age, animals co-exposed to ozone + HDM exhibited a decline in total circulating leukocyte numbers and increased total circulating lymphocyte frequency. At 3 months of age, blood CD4+/CD25+ lymphocytes were increased with ozone + HDM. At 6 months of age, CD4+/CD25+ and CD8+/CD25+ lymphocyte populations increased in both blood and lavage of ozone + HDM animals. Overall volume of CD25+ cells within airway mucosa increased with HDM exposure. Ozone did not have an additive effect on volume of mucosal CD25+ cells in HDM-exposed animals, but did alter the anatomical distribution of this cell type throughout the proximal and distal airways. We conclude that a window of postnatal development is sensitive to air pollutant and allergen exposure, resulting in immunomodulation of peripheral blood and airway lymphocyte frequency and trafficking.

  2. Long-term exposure to ambient ozone and mortality: a quantitative systematic review and meta-analysis of evidence from cohort studies

    PubMed Central

    Atkinson, R W; Butland, B K; Dimitroulopoulou, C; Heal, M R; Stedman, J R; Carslaw, N; Jarvis, D; Heaviside, C; Vardoulakis, S; Walton, H; Anderson, H R

    2016-01-01

    Objectives While there is good evidence for associations between short-term exposure to ozone and a range of adverse health outcomes, the evidence from narrative reviews for long-term exposure is suggestive of associations with respiratory mortality only. We conducted a systematic, quantitative evaluation of the evidence from cohort studies, reporting associations between long-term exposure to ozone and mortality. Methods Cohort studies published in peer-reviewed journals indexed in EMBASE and MEDLINE to September 2015 and PubMed to October 2015 and cited in reviews/key publications were identified via search strings using terms relating to study design, pollutant and health outcome. Study details and estimate information were extracted and used to calculate standardised effect estimates expressed as HRs per 10 ppb increment in long-term ozone concentrations. Results 14 publications from 8 cohorts presented results for ozone and all-cause and cause-specific mortality. We found no evidence of associations between long-term annual O3 concentrations and the risk of death from all causes, cardiovascular or respiratory diseases, or lung cancer. 4 cohorts assessed ozone concentrations measured during the warm season. Summary HRs for cardiovascular and respiratory causes of death derived from 3 cohorts were 1.01 (95% CI 1.00 to 1.02) and 1.03 (95% CI 1.01 to 1.05) per 10 ppb, respectively. Conclusions Our quantitative review revealed a paucity of independent studies regarding the associations between long-term exposure to ozone and mortality. The potential impact of climate change and increasing anthropogenic emissions of ozone precursors on ozone levels worldwide suggests further studies of the long-term effects of exposure to high ozone levels are warranted. PMID:26908518

  3. Persistent rhinitis and epithelial remodeling induced by cyclic ozone exposure in the nasal airways of infant monkeys

    PubMed Central

    Ballinger, Carol A.; Plopper, Charles G.; McDonald, Ruth J.; Bartolucci, Alfred A.; Postlethwait, Edward M.; Harkema, Jack R.

    2011-01-01

    Children chronically exposed to high levels of ozone (O3), the principal oxidant pollutant in photochemical smog, are more vulnerable to respiratory illness and infections. The specific factors underlying this differential susceptibility are unknown but may be related to air pollutant-induced nasal alterations during postnatal development that impair the normal physiological functions (e.g., filtration and mucociliary clearance) serving to protect the more distal airways from inhaled xenobiotics. In adult animal models, chronic ozone exposure is associated with adaptations leading to a decrease in airway injury. The purpose of our study was to determine whether cyclic ozone exposure induces persistent morphological and biochemical effects on the developing nasal airways of infant monkeys early in life. Infant (180-day-old) rhesus macaques were exposed to 5 consecutive days of O3 [0.5 parts per million (ppm), 8 h/day; “1-cycle”] or filtered air (FA) or 11 biweekly cycles of O3 (FA days 1–9; 0.5 ppm, 8 h/day on days 10–14; “11-cycle”). The left nasal passage was processed for light microscopy and morphometric analysis. Mucosal samples from the right nasal passage were processed for GSH, GSSG, ascorbate (AH2), and uric acid (UA) concentration. Eleven-cycle O3 induced persistent rhinitis, squamous metaplasia, and epithelial hyperplasia in the anterior nasal airways of infant monkeys, resulting in a 39% increase in the numeric density of epithelial cells. Eleven-cycle O3 also induced a 65% increase in GSH concentrations at this site. The persistence of epithelial hyperplasia was positively correlated with changes in GSH. These results indicate that early life ozone exposure causes persistent nasal epithelial alterations in infant monkeys and provide a potential mechanism for the increased susceptibility to respiratory illness exhibited by children in polluted environments. PMID:21131400

  4. The characterization and comparison of ozone exposure indices used in assessing the response of loblolly pine to ozone

    NASA Astrophysics Data System (ADS)

    Lefohn, Allen S.; Shadwick, Douglas S.; Somerville, Matthew C.; Chappelka, Arthur H.; Lockaby, B. Graeme; Meldahl, Ralph S.

    Using the 1988 and 1989 experimental results obtained for two loblolly pine half-sibling families (GAKR 15-23 and GAKR 15-91) at the Auburn University intensive field research site, we: (1) explored the performance of a set of exposure indices; (2) characterized the ambient air and charcoal-filtered air treatments at Auburn and compared the values of the O 3 exposure indices with those values calculated for ambient O 3 monitors for a select set of sites; (3) identified and characterized O 3 treatments in the Auburn open-top exposure chambers where an adverse effect was noted; and (4) identified where such experimental exposure regimes occurred under ambient conditions. We found that the SUMO exposure index did not perform adequately. We were unable to distinguish among the performances of the SUM06, W126, and SUM08 exposure indices. The results of the analyses of six estimated logistic parameters for a model of diameter 2 × height ( d 2h ) vs time indicated O 3 effects for both families. At pH 4.3 (near ambient conditions), a response to O 3 was detected in the NF × 2.5 treatments for both families for t2, the approximate time of maximum growth during the second year. Using ln (final d 2h ), family 23 did not show O 3 effects. A comparison of the exposures experienced in the NF × 2.5 treatments with those occurring under ambient conditions at other locations showed that in 1983 and 1986, the San Bernardino County (CA) site experienced O 3 exposures similar to those values experienced at the NF × 2.5 treatments in 1989.

  5. Projected carbon dioxide to increase grass pollen and allergen exposure despite higher ozone levels.

    PubMed

    Albertine, Jennifer M; Manning, William J; DaCosta, Michelle; Stinson, Kristina A; Muilenberg, Michael L; Rogers, Christine A

    2014-01-01

    One expected effect of climate change on human health is increasing allergic and asthmatic symptoms through changes in pollen biology. Allergic diseases have a large impact on human health globally, with 10-30% of the population affected by allergic rhinitis and more than 300 million affected by asthma. Pollen from grass species, which are highly allergenic and occur worldwide, elicits allergic responses in 20% of the general population and 40% of atopic individuals. Here we examine the effects of elevated levels of two greenhouse gases, carbon dioxide (CO2), a growth and reproductive stimulator of plants, and ozone (O3), a repressor, on pollen and allergen production in Timothy grass (Phleum pratense L.). We conducted a fully factorial experiment in which plants were grown at ambient and/or elevated levels of O3 and CO2, to simulate present and projected levels of both gases and their potential interactive effects. We captured and counted pollen from flowers in each treatment and assayed for concentrations of the allergen protein, Phl p 5. We found that elevated levels of CO2 increased the amount of grass pollen produced by ∼50% per flower, regardless of O3 levels. Elevated O3 significantly reduced the Phl p 5 content of the pollen but the net effect of rising pollen numbers with elevated CO2 indicate increased allergen exposure under elevated levels of both greenhouse gases. Using quantitative estimates of increased pollen production and number of flowering plants per treatment, we estimated that airborne grass pollen concentrations will increase in the future up to ∼200%. Due to the widespread existence of grasses and the particular importance of P. pratense in eliciting allergic responses, our findings provide evidence for significant impacts on human health worldwide as a result of future climate change.

  6. Projected carbon dioxide to increase grass pollen and allergen exposure despite higher ozone levels.

    PubMed

    Albertine, Jennifer M; Manning, William J; DaCosta, Michelle; Stinson, Kristina A; Muilenberg, Michael L; Rogers, Christine A

    2014-01-01

    One expected effect of climate change on human health is increasing allergic and asthmatic symptoms through changes in pollen biology. Allergic diseases have a large impact on human health globally, with 10-30% of the population affected by allergic rhinitis and more than 300 million affected by asthma. Pollen from grass species, which are highly allergenic and occur worldwide, elicits allergic responses in 20% of the general population and 40% of atopic individuals. Here we examine the effects of elevated levels of two greenhouse gases, carbon dioxide (CO2), a growth and reproductive stimulator of plants, and ozone (O3), a repressor, on pollen and allergen production in Timothy grass (Phleum pratense L.). We conducted a fully factorial experiment in which plants were grown at ambient and/or elevated levels of O3 and CO2, to simulate present and projected levels of both gases and their potential interactive effects. We captured and counted pollen from flowers in each treatment and assayed for concentrations of the allergen protein, Phl p 5. We found that elevated levels of CO2 increased the amount of grass pollen produced by ∼50% per flower, regardless of O3 levels. Elevated O3 significantly reduced the Phl p 5 content of the pollen but the net effect of rising pollen numbers with elevated CO2 indicate increased allergen exposure under elevated levels of both greenhouse gases. Using quantitative estimates of increased pollen production and number of flowering plants per treatment, we estimated that airborne grass pollen concentrations will increase in the future up to ∼200%. Due to the widespread existence of grasses and the particular importance of P. pratense in eliciting allergic responses, our findings provide evidence for significant impacts on human health worldwide as a result of future climate change. PMID:25372614

  7. Exposure information in environmental health research: Current opportunities and future directions for particulate matter, ozone, and toxic air pollutants

    SciTech Connect

    McKone, Thomas E.; Ryan, P. Barry; Ozkaynak, Haluk

    2007-02-01

    Understanding and quantifying outdoor and indoor sources of human exposure are essential but often not adequately addressed in health-effects studies for air pollution. Air pollution epidemiology, risk assessment, health tracking and accountability assessments are examples of health-effects studies that require but often lack adequate exposure information. Recent advances in exposure modeling along with better information on time-activity and exposure factors data provide us with unique opportunities to improve the assignment of exposures for both future and ongoing studies linking air pollution to health impacts. In September 2006, scientists from the US Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) along with scientists from the academic community and state health departments convened a symposium on air pollution exposure and health in order to identify, evaluate, and improve current approaches for linking air pollution exposures to disease. This manuscript presents the key issues, challenges and recommendations identified by the exposure working group, who used cases studies of particulate matter, ozone, and toxic air pollutant exposure to evaluate health-effects for air pollution. One of the over-arching lessons of this workshop is that obtaining better exposure information for these different health-effects studies requires both goal-setting for what is needed and mapping out the transition pathway from current capabilities to meeting these goals. Meeting our long-term goals requires definition of incremental steps that provide useful information for the interim and move us toward our long-term goals. Another over-arching theme among the three different pollutants and the different health study approaches is the need for integration among alternate exposure assessment approaches. For example, different groups may advocate exposure indicators, biomonitoring, mapping methods (GIS), modeling, environmental media

  8. Biomarkers of Oxidative Stress Study IV. Are Antioxidants Markers of Ozone Exposure?

    EPA Science Inventory

    To determine whether the oxidative effects of ozone would result in losses of antioxidants from plasma, and possibly bronchoalveolar lavage fluid (BALF). This research is part of a comprehensive, multilaboratory validation study searching for noninvasive biomarkers of oxidative ...

  9. Changes in CR-39 proton sensitivity due to prolonged exposure to high vacuums relevant to the National Ignition Facility and OMEGA.

    PubMed

    Manuel, M J-E; Rosenberg, M J; Sinenian, N; Rinderknecht, H; Zylstra, A B; Séguin, F H; Frenje, J; Li, C K; Petrasso, R D

    2011-09-01

    When used at facilities like OMEGA and the NIF, CR-39 is exposed to high vacuum environments before and after irradiation by charged particles and neutrons. Using an electrostatic linear accelerator at MIT, studies have been conducted to investigate the effects of high vacuum exposure on the sensitivity of CR-39 to fusion protons in the ~1-9 MeV energy range. High vacuum conditions, of order 10(-5) Torr, experienced by CR-39 samples at these facilities were emulated. It is shown that vacuum exposure times longer than ~16 h before proton irradiation result in a decrease in proton sensitivity, whereas no effect was observed for up to 67 h of vacuum exposure after proton irradiation. CR-39 sensitivity curves are presented for samples with prolonged exposure to high vacuum before and after proton irradiation.

  10. Impact of sex and ozone exposure on the course of pneumonia in wild type and SP-A (−/−) mice

    PubMed Central

    Mikerov, Anatoly N.; Hu, Sanmei; Durrani, Faryal; Gan, Xiaozhuang; Wang, Guirong; Umstead, Todd M.; Phelps, David S.; Floros, Joanna

    2012-01-01

    Female mice exhibited higher survival rate than males after pneumonia, with a reversal of this pattern following ozone exposure. Surfactant protein A (SP-A) plays an important role in innate immunity and SP-A (−/−) mice were more susceptible to pneumonia than wild type mice. Here, we investigated underlying mechanisms of the differential susceptibility of mice to pneumonia. Wild type and SP-A (−/−) C57BL/6J male and female mice were exposed to ozone or filtered air (FA) and then infected intratracheally with Klebsiella pneumoniae. Blood, spleen, and lung were analyzed for bacterial counts, lung and spleen weights, and sex hormone and cortisol levels were measured in plasma within two days post-infection. We found: 1) in the absence of ozone-induced oxidative stress, males had higher level of bacterial dissemination compared to females; ozone exposure decreased pulmonary clearance in both sexes and ozone-exposed females were more affected than males; 2) ozone exposure increased lung weight, but decreased spleen weight in both sexes, and in both cases ozone-exposed females were affected the most; 3) plasma cortisol levels in infected mice changed: ozone-exposed > FA-exposed, females > males, and infected > non-infected; 4) no major sex hormone differences were observed in the studied conditions; 5) differences between wild type and SP-A (−/−) mice were observed in some of the studied conditions. We concluded that reduced pulmonary clearance, compromised spleen response to infection, and increased cortisol levels in ozone-exposed females, and the higher level of lung bacterial dissemination in FA-exposed males, contribute to the previously observed survival outcomes. PMID:22285567

  11. Fine Ambient Particulate and Ozone Co-Exposures in Durham, North Carolina: Influence of Season on Particle Chemistry and Cardiovascular Responses in Rats

    EPA Science Inventory

    Epidemiological studies have shown that the presence of one air pollutant modifies the cardiovascular health effects of another while controlled exposure studies in humans have documented synergistic effects of co-exposure to ambient particulate matter (PM) and ozone (O3) on bloo...

  12. Transport across rat trachea in vitro after exposure to cytoskeleton-active drugs in vitro or to ozone in vivo

    SciTech Connect

    Rasmussen, R.E.; Bhalla, D.K.

    1989-03-01

    Full-length tracheas from Sprague-Dawley rats were exposed to cytoskeleton-active drugs in short-term organ culture, and the permeability of the tracheal epithelium was measured by instilling radiotracers into the lumen and assay of the radioactivity appearing in the external bathing medium. In vitro treatment with cytochalasin D (cyto D, 2-10 x 10(-6) M) increased the rate of movement of (14C)mannitol across the epithelium. Exposure to vinblastine (VB, 10(-4) M) alone had no significant effect. However, VB in combination with cyto D increased the permeability in a dose-dependent manner. In vivo exposure to ozone (O3, 0.8 or 2.0 ppm, 2 h) had only a slight effect on the rate of movement of the tracer as measured in vitro immediately after exposure. At 24 h postexposure there was no significant difference in permeability between ozone- and air-exposed tracheas. Prior in vivo O3 exposure sensitized the tracheas to the in vitro effects of cyto D; treatment of O3-exposed tracheas with cyto D immediately after O3 exposure produced a greater than additive effect on permeability measured in vitro. VB at concentrations up to 10(-4) M had no enhancing effect on permeability in O3-exposed tracheas. Sham exposure to clean air did not affect permeability compared to untreated (shelf) controls. Electron microscopic studies demonstrated penetration of horseradish peroxidase into intercellular spaces in the tracheas treated in vitro with cyto D or cyto D plus VB. Cyto D is known to affect intracellular microfilaments that have attachments at or near the cell surface, while VB affects microtubules associated with internal cellular structures. Therefore, the synergistic effect on tracheal permeability observed with O3 and cyto D, but not with O3 and VB, suggests that O3 may change cell surface structures associated with the microfilamentous cytoskeleton.

  13. Biomarkers of Oxidative Stress Study V: Ozone exposure of rats and its effect on lipids, proteins and DNA in plasma and urine

    PubMed Central

    Kadiiska, Maria B.; Basu, Samar; Brot, Nathan; Cooper, Christopher; Csallany, A. Saari; Davies, Michael J.; George, Magdalene M.; Murray, Dennis M.; Roberts, L. Jackson; Shigenaga, Mark K.; Sohal, Rajindar S.; Stocker, Roland; Van Thiel, David H.; Wiswedel, Ingrid; Hatch, Gary E.; Mason, Ronald P.

    2014-01-01

    Ozone exposure effect on free radical-catalyzed oxidation products of lipids, proteins and DNA in the plasma and urine of rats was studied as a continuation of the international Biomarker of Oxidative Stress Study (BOSS) sponsored by NIEHS/NIH. The goal was to identify a biomarker for ozone-induced oxidative stress and to assess whether inconsistent results often reported in the literature might be due to the limitations of the available methods for measuring the various types of oxidative products. The time and dose-dependent effects of ozone exposure on rat plasma lipid hydroperoxides, malondialdehyde, F2-isoprostanes, protein carbonyls, methionine oxidation, tyrosine- and phenylalanine oxidation products, as well as urinary malondialdehyde and F2-isoprostanes were investigated with various techniques. The criterion used to recognize a marker in the model of ozone exposure was that a significant effect could be identified and measured in a biological fluid seen at both doses at more than one time point. No statistically significant differences between the experimental and control groups at either ozone dose and time point studied could be identified in this study. Tissue samples were not included. Despite all the work accomplished in the BOSS study of ozone, no available product of oxidation in biological fluid has yet met the required criteria of being a biomarker. The current negative findings as a consequence of ozone exposure are of great importance, because they document that in complex systems, as the present in vivo experiment, the assays used may not provide meaningful data of ozone oxidation, especially in human studies. PMID:23608465

  14. A Time-Stratified Case-Crossover Study of Ambient Ozone Exposure and Emergency Department Visits for Specific Respiratory Diagnoses in California (2005–2008)

    PubMed Central

    Malig, Brian J.; Pearson, Dharshani L.; Chang, Yun Brenda; Broadwin, Rachel; Basu, Rupa; Green, Rochelle S.; Ostro, Bart

    2015-01-01

    Background: Studies have explored ozone’s connection to asthma and total respiratory emergency department visits (EDVs) but have neglected other specific respiratory diagnoses despite hypotheses relating ozone to respiratory infections and allergic responses. Objective: We examined relationships between ozone and EDVs for respiratory visits, including specifically acute respiratory infections (ARI), asthma, pneumonia, chronic obstructive pulmonary disease (COPD), and upper respiratory tract inflammation (URTI). Methods: We conducted a multi-site time-stratified case-crossover study of ozone exposures for approximately 3.7 million respiratory EDVs from 2005 through 2008 among California residents living within 20 km of an ozone monitor. Conditional logistic regression was used to estimate associations by climate zone. Random effects meta-analysis was then applied to estimate pooled excess risks (ER). Effect modification by season, distance from the monitor and individual demographic characteristics (i.e., age, race/ethnicity, sex, and payment method), and confounding by other gaseous air pollutants were also investigated. Meta-regression was utilized to explore how climate zone–level meteorological, demographic, and regional differences influenced estimates. Results: We observed ozone-associated increases in all respiratory, asthma, and ARI visits, which were slightly larger in the warm season [asthma ER per 10-ppb increase in mean of same and previous 3 days ozone exposure (lag03) = 2.7%, 95% CI: 1.5, 3.9; ARI ERlag03 = 1.4%, 95% CI: 0.8, 1.9]. EDVs for pneumonia, COPD, and URTI were also significantly associated with ozone exposure over the whole year, but typically more consistently so during the warm season. Conclusions: Short-term ozone exposures among California residents living near an ozone monitor were positively associated with EDVs for asthma, ARI, pneumonia, COPD, and URTI from 2005 through 2008. Those associations were typically larger and more

  15. Foliar injury, leaf gas exchange and biomass responses of black cherry (Prunus serotina Ehrh.) half-sibling families to ozone exposure.

    PubMed

    Kouterick, K B; Skelly, J M; Fredericksen, T S; Steiner, K C; Kolb, T E; Ferdinand, J A

    2000-01-01

    Open pollinated families of black cherry seedlings were studied to determine genotypic differences in foliar ozone injury and leaf gas exchange in 1994 and growth response following three growing seasons. An O(3)-sensitive half-sibling family (R-12) and an O(3)-tolerant half-sibling family (MO-7) planted in natural soil were studied along with generic nursery stock (NS) seedlings. Ozone exposure treatments were provided through open top chambers and consisted of 50, 75, and 97% of ambient ozone, and open plots from May 9 to August 26, 1994. Ambient ozone concentrations reached an hourly peak of 88 ppb with 7-hour averages ranging from 39 to 46 ppb. Seedlings in the 50 and 75% of ambient chambers were never exposed to greater than 80 ppb O(3). Visible foliar ozone injury (stipple) was significantly higher for R-12 seedlings than MO-7 seedlings and increased with increasing ozone exposures. For the chamber treatments averaged over all families, there was no significant difference in stomatal conductance and net photosynthetic rates, but there was a significant decrease in root biomass, and a significant decrease in root/shoot ratio between the 50 and 97% of ambient chambers. Stomatal conductance and net photosynthetic rates were significantly different between families with R-12 seedlings generally greater than MO-7 seedlings. The R-12 seedlings had a 7.5 mmol m(-2) increase in ozone uptake compared to MO-7, and at the same cumulative O(3) exposure R-12 exhibited 40.9% stippled leaf area, whereas MO-7 had 9.2% stippled leaf area. Significant differences were observed in stem volume growth and total final biomass between the open-top chambers and open plots. Although R-12 had the most severe foliar ozone injury, this family had significantly greater stem volume growth and total final biomass than MO-7 and NS seedlings. Root:shoot ratio was not significantly different between MO-7 and R-12 seedlings. PMID:15093015

  16. Prolonged L-alanine exposure induces changes in metabolism, Ca(2+) handling and desensitization of insulin secretion in clonal pancreatic beta-cells.

    PubMed

    McClenaghan, Neville H; Scullion, Siobhan M; Mion, Brian; Hewage, Chandralal; Malthouse, J Paul G; Flatt, Peter R; Newsholme, Philip; Brennan, Lorraine

    2009-02-01

    Acute insulin-releasing actions of amino acids have been studied in detail, but comparatively little is known about the beta-cell effects of long-term exposure to amino acids. The present study examined the effects of prolonged exposure of beta-cells to the metabolizable amino acid L-alanine. Basal insulin release or cellular insulin content were not significantly altered by alanine culture, but acute alanine-induced insulin secretion was suppressed by 74% (P<0.001). Acute stimulation of insulin secretion with glucose, KCl or KIC (2-oxoisocaproic acid) following alanine culture was not affected. Acute alanine exposure evoked strong cellular depolarization after control culture, whereas AUC (area under the curve) analysis revealed significant (P<0.01) suppression of this action after culture with alanine. Compared with control cells, prior exposure to alanine also markedly decreased (P<0.01) the acute elevation of [Ca(2+)](i) (intracellular [Ca(2+)]) induced by acute alanine exposure. These diminished stimulatory responses were partially restored after 18 h of culture in the absence of alanine, indicating reversible amino-acid-induced desensitization. (13)C NMR spectra revealed that alanine culture increased glutamate labelling at position C4 (by 60%; P<0.01), as a result of an increase in the singlet peak, indicating increased flux through pyruvate dehydrogenase. Consistent with this, protein expression of the pyruvate dehydrogenase kinases PDK2 and PDK4 was significantly reduced. This was accompanied by a decrease in cellular ATP (P<0.05), consistent with diminished insulin-releasing actions of this amino acid. Collectively, these results illustrate the phenomenon of beta-cell desensitization by amino acids, indicating that prolonged exposure to alanine can induce reversible alterations to metabolic flux, Ca(2+) handling and insulin secretion. PMID:18702613

  17. Ozone exposure causes a decoupling of conductance and photosynthesis: implications for the Ball-Berry stomatal conductance model.

    PubMed

    Lombardozzi, Danica; Sparks, Jed P; Bonan, Gordon; Levis, Samuel

    2012-07-01

    Industrialization has significantly altered atmospheric chemistry by increasing concentrations of chemicals such as nitrogen oxides (NO( x )) and volatile organic carbon, which react in the presence of sunlight to produce tropospheric ozone (O(3)). Ozone is a powerful oxidant that causes both visual and physiological damage to plants, impairing the ability of the plant to control processes like photosynthesis and transpiration. Damage to photosynthesis and stomatal conductance does not always occur at the same rate, which generates a problem when using the Ball-Berry model to predict stomatal conductance because the calculations directly rely on photosynthesis rates. The goals of this work were to develop a modeling framework to modify Ball-Berry stomatal conductance predictions independently of photosynthesis and to test the framework using experimental data. After exposure to elevated O(3) in open-top chambers, photosynthesis and stomatal conductance in tulip poplar changed at different rates through time. We were able to accurately model observed photosynthetic and stomatal conductance responses to chronic O(3) exposure in a Ball-Berry framework by adjusting stomatal conductance in addition to photosynthesis. This led to a significant improvement in the modeled ability to predict both photosynthesis and stomatal conductance responses to O(3).

  18. Serum biomarkers in young adult and aged Brown Norway (BN) rats following episodic (weekly) ozone exposure

    EPA Science Inventory

    Ozone (03) is an air pollutant that is associated with cardiovascular and respiratory diseases. Older adults are considered to be particularly susceptible to oxidant air pollutants such as 03. Serum biomarkers are being sought that would lead to better predictions of susceptibili...

  19. Provisional assessment of recent studies on health and ecological effects of ozone exposure

    EPA Science Inventory

    A reconsideration of the national ambient air quality standards (NAAQS) for O3 is currently underway. The last Air Quality Criteria Document for Ozone and Related Photochemical Oxidants (O...

  20. SUBCHRONIC EPISODIC EXPOSURE OF RATS TO DIESEL PLUS OZONE INDUCES MINIMAL CARDIOPULMONARY EFFECTS

    EPA Science Inventory

    Diesel exhaust (DE) emissions contribute to near-road air pollution and have been shown to induce a variety of cardiovascular and pulmonary abnormalities in animals and humans. Since high ozone concentrations are often associated with increased traffic-related emissions, we postu...

  1. Impact of rising greenhouse gas concentrations on future tropical ozone and UV exposure

    NASA Astrophysics Data System (ADS)

    Meul, Stefanie; Dameris, Martin; Langematz, Ulrike; Abalichin, Janna; Kerschbaumer, Andreas; Kubin, Anne; Oberländer-Hayn, Sophie

    2016-03-01

    Future projections of tropical total column ozone (TCO) are challenging, as its evolution is affected not only by the expected decline of ozone depleting substances but also by the uncertain increase of greenhouse gas (GHG) emissions. To assess the range of tropical TCO projections, we analyze simulations with a chemistry-climate model forced by three different GHG scenarios (Representative Concentration Pathway (RCP) 4.5, RCP6.0, and RCP8.5). We find that tropical TCO will be lower by the end of the 21st century compared to the 1960s in all scenarios with the largest decrease in the medium RCP6.0 scenario. Uncertainties of the projected TCO changes arise from the magnitude of stratospheric column decrease and tropospheric ozone increase which both strongly vary between the scenarios. In the three scenario simulations the stratospheric column decrease is not compensated by the increase in tropospheric ozone. The concomitant increase in harmful ultraviolet irradiance reaches up to 15% in specific regions in the RCP6.0 scenario.

  2. Glycoalkaloid levels in potato tubers and leaves after intermittent plant exposure to ozone

    SciTech Connect

    Speroni, J.J.; Pell, E.J.; Weissberger, W.C.

    1981-01-01

    Irish potato vines of Norland and Kennebec cultivars were exposed to 387 ..mu..g/m/sup 3/ ozone for 3 hr once every wk throughout their growth. Tubers of Norland and Kennebec were harvested at 120 and 140 days, respectively, from exposed and non-exposed plants. The experiment was conducted in 1977 and again in 1978. Ozone induced severe foliar injury to Norland and slight injury to leaves of Kennebec. Tubers from ozone treated plants displayed a significant reduction (0.35 mg TTGA/100 g fresh weight tuber tissue) in tuber total glycoalkaloids (TTGA) when expressed on a fresh weight basis. However, since differences were not detected for TTGA on a dry-weight basis, the fresh-weight TTGA differences may only reflect variations in moisture content. In a separate experiment, both Norland and Kennebec were exposed to 488 ..mu..g/m/sup 3/ ozone for 3 hr when the plants were 18 days old. When leaves were harvested three days later, no significant differeces were detected between leaf total glycoalkaloid (LTGA) levels of treated and nontreated plants. 26 references, 2 tables.

  3. Genotoxic effects in the Eastern mudminnow (Umbra pygmaea) after prolonged exposure to River Rhine water, as assessed by use of the in vivo SCE and Comet assays.

    PubMed

    Penders, E J M; Spenkelink, A; Hoogenboezem, W; Rotteveel, S G P; Maas, J L; Alink, G M

    2012-05-01

    The production of drinking water from river water requires a certain minimal river water quality. The Association of River Rhine Water Works (RIWA), therefore, operates a monitoring network. In vitro mutagenicity studies have shown that the genotoxicity of the River Rhine water steadily decreased from 1981 until 2001. Compared to a study in 1978, a decrease in genotoxicity was also observed in an in vivo genotoxicity study in 2005, in which Eastern mudminnows (Umbra pygmaea) were exposed to River Rhine water, and gill cells were used for the Sister Chromatid Exchange (SCE) test and the Comet assay. In this 2005 study, the in vivo genotoxicity increased upon extending exposure of the fish from 3 to 11 days. Therefore, the objectives of this study were to investigate (i) whether new data corroborate that in vivo genotoxicity of River Rhine water is at present lower than in 1978, (ii) whether the Comet assay is a suitable alternative to the SCE assay, and (iii) whether further prolonged exposure results in a further increase in in vivo genotoxicity. The new data corroborate that in vivo genotoxicity of River Rhine water is at present lower than in 1978. The Comet assay is a useful addition but does not provide a substitute for the SCE endpoint in these in vivo genotoxicity studies. Prolonging the exposure time of Eastern mudminnows to River Rhine water from 11 to 42 days did not give a significant increase in SCEs and DNA damage (Comet assay) in gill cells.

  4. Effects of short- and long-term exposure to ozone on heart rate and blood pressure of emphysematous rats

    SciTech Connect

    Uchiyama, I.; Yokoyama, E.

    1989-02-01

    Electrocardiogram and arterial blood pressure of elastase-treated emphysematous rats (E rats) and saline-treated control rats (S rats) were recorded continuously during exposure to either 1 ppm ozone (O/sub 3/) for 3 hr or 0.5 ppm O/sub 3/ for 6 hr. The heart rates (HRs) of both groups decreased to about 50 and 65% of the initial levels at the end of 1 ppm and 0.5 ppm O/sub 3/ exposure, respectively. Mean arterial blood pressures (MAPs) also decreased to about 76 and 82%, respectively. There was no significant difference in these responses between E and S rats, although the levels of HRs and MAPs of the E rats were always a little lower than those of the S rats. Another group of E and S rats was continuously exposed to 0.2 ppm O/sub 3/ for 4 weeks. The HRs of both E and S groups decreased to about 81 and 88% of the initial levels on the first day, respectively, although they recovered completely by the third day. No significant difference in the variation of HRs during exposure was noted between E and S rats. However, the HR responses of these rats to a challenge exposure of 0.8 ppm O/sub 3/ for 1.5 hr appeared to be different. That is, S rats were more tolerant of the challenge exposure to O/sub 3/ for 1.5 hr than the E rats.

  5. Responses of Fraxinus excelsior L. seedlings to ambient ozone exposure in urban and mountain areas based on physiological characteristics and antioxidant activity.

    PubMed

    Parvanova, Petya; Tzvetkova, Nikolina; Bratanova-Doncheva, Svetla; Chipev, Nesho; Fikova, Radka; Donev, Evgeni

    2013-07-01

    Effects of ozone on the sensitive tree species Fraxinus excelsior L. exposed to ambient air were investigated. The dynamics of photosynthesis, transpiration, stomatal conductance and the activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in three-year-old ash seedlings were studied during a four-month period (June-September). Seedlings were exposed to ambient ozone in an urban (the Central City Park of Sofia - Borisova Gradina) and a mountain (Plana Mountain) area in Bulgaria. The sites were located near climate monitoring stations, providing data on ozone concentrations and meteorological parameters. Ozone exposure at the mountain site (AOT40) was more than two times higher compared to the urban site. Significantly higher values of sun radiation, transpiration, stomatal conductance and enzyme activity at the mountain site were also observed. At the urban site higher values of temperature and air humidity were registered. Effects of the measured variables on ash seedlings were complex and interdependent. No direct effect of ozone concentration in ambient air on the leaf physiology and biochemistry could be proved. However, intensified SOD and CAT activity in the presence of elevated ozone suggested antioxidant reaction in response to ozone uptake. PMID:23760537

  6. Chemical modification of coating of Pinus halepensis pollen by ozone exposure.

    PubMed

    Naas, Oumsaad; Mendez, Maxence; Quijada, Melesio; Gosselin, Sylvie; Farah, Jinane; Choukri, Ali; Visez, Nicolas

    2016-07-01

    Pollen coating, located on the exine, includes an extractible lipid fraction. The modification of the pollen coating by air pollutants may have implications on the interactions of pollen with plant stigmas and human cells. Pinus halepensis pollen was exposed to ozone in vitro and the pollen coating was extracted with organic solvent and analyzed by GC-MS. Ozone has induced chemical changes in the coating as observed with an increase in dicarboxylic acids, short-chain fatty acids and aldehydes. 4-Hydroxybenzaldehyde was identified as the main reaction product and its formation was shown to occur both on native pollen and on defatted pollen. 4-Hydroxybenzaldehyde is very likely formed via the ozonolysis of acid coumaric-like monomers constitutive of the sporopollenin. Modification of pollen coating by air pollutants should be accounted for in further studies on effect of pollution on germination and on allergenicity.

  7. Chemical modification of coating of Pinus halepensis pollen by ozone exposure.

    PubMed

    Naas, Oumsaad; Mendez, Maxence; Quijada, Melesio; Gosselin, Sylvie; Farah, Jinane; Choukri, Ali; Visez, Nicolas

    2016-07-01

    Pollen coating, located on the exine, includes an extractible lipid fraction. The modification of the pollen coating by air pollutants may have implications on the interactions of pollen with plant stigmas and human cells. Pinus halepensis pollen was exposed to ozone in vitro and the pollen coating was extracted with organic solvent and analyzed by GC-MS. Ozone has induced chemical changes in the coating as observed with an increase in dicarboxylic acids, short-chain fatty acids and aldehydes. 4-Hydroxybenzaldehyde was identified as the main reaction product and its formation was shown to occur both on native pollen and on defatted pollen. 4-Hydroxybenzaldehyde is very likely formed via the ozonolysis of acid coumaric-like monomers constitutive of the sporopollenin. Modification of pollen coating by air pollutants should be accounted for in further studies on effect of pollution on germination and on allergenicity. PMID:27155099

  8. Short-term respiratory effects of 0. 12 ppm ozone exposure in volunteers with chronic obstructive pulmonary disease

    SciTech Connect

    Linn, W.S.; Fischer, D.A.; Medway, D.A.; Anzar, U.T.; Spier, C.E.; Valencia, L.M.; Venet, T.G.; Hackney, J.D.

    1982-06-01

    Twenty-five volunteers with chronic obstructive pulmonary disease of mild to moderately severe degree underwent 1-h exposures to 0.12 ppm ozone (O/sub 2/) in purified air with intermittent mild exercise. Their responses were assessed in terms of forced expiratory performance, ear oximetry, and reported symptoms. Control studied consisted of similar exposures to purified air alone. Control studies were separated from O/sub 2/ exposures by 1 month, and the order was randomized. All studies took place in a controlled-environment chamber, and were preceded by approximately 1 h of rest in a purified-air environment. No significant disturbances in forced expiratory performance or symptoms attributable to O/sub 2/ exposure were found. A slight but significant tendency to decreased arterial hemoglobin oxygen saturation (SaO/sub 2/) during exercise in O/sub 2/ was observed. The decrement in SaO/sub 2/ with O/sub 2/ relative to clean air (mean 1.3%) was near the limit of resolution of the ear oximeter test and was detected by signal averaging, thus its physiologic or clinical significance is uncertain.

  9. Effects of Drought Stress and Ozone Exposure on Isoprene Emissions from Oak Seedlings in Texas

    NASA Astrophysics Data System (ADS)

    Madronich, M. B.; Harte, A.; Schade, G. W.

    2014-12-01

    Isoprene is the dominant hydrocarbon emitted by plants to the atmosphere with an approximate global emission of 550 Tg C yr-1. Isoprene emission studies have elucidated plants' isoprene production capacity, and the controlling factors of instantaneous emissions. However, it is not yet well understood how long-term climatic factors such as drought and increasing ozone concentrations affect isoprene emission rates. Drought reduces photosynthetic activity and is thus expected to reduce isoprene emission rate, since isoprene production relies on photosynthates. On the other hand, ozone is also known to negatively affect photosynthesis rates, but can instead increase isoprene emissions. These apparent inconsistencies and a lack of experimental data make it difficult to accurately parameterize isoprene emission responses to changing environmental conditions. The objective of this work is to reduce some of these uncertainties, using oak seedlings as a study system. Our project focuses on isoprene emission responses of oak trees to typical summer drought and high ozone conditions in Texas. We report on experiments conducted using a laboratory whole-plant chamber and leaf-level data obtained from greenhouse-grown seedlings. The chamber experiment studied the effects of ozone and drought on isoprene emissions from >3 year old oak seedlings under controlled conditions of photosynthetically active radiation (PAR), temperature, soil-moisture and the chamber's air composition. Stress in plants was induced by manipulating potted soil-moisture and ozone concentration in the chamber. The greenhouse study focused on understanding the effects of drought under Texas climatic conditions. For this study we used two year old seedlings of water oak (Quercus nigra) and post oak (Quercus stellata). Temperature, humidity and light in the greenhouse followed local conditions. Leaf-level conductance, photosynthesis measurements and isoprene sampling were carried out under controlled leaf

  10. A discrete-time analysis of the effects of more prolonged exposure to neighborhood poverty on the risk of smoking initiation by age 25.

    PubMed

    Kravitz-Wirtz, Nicole

    2016-01-01

    Evidence suggests that individuals who initiate smoking at younger ages are at increased risk for future tobacco dependence and continued use as well as for numerous smoking-attributable health problems. Identifying individual, household, and to a far lesser extent, contextual factors that predict early cigarette use has garnered considerable attention over the last several decades. However, the majority of scholarship in this area has been cross-sectional or conducted over relatively short windows of observation. Few studies have investigated the effects of more prolonged exposure to smoking-related risk factors, particularly neighborhood characteristics, from childhood through early adulthood. Using the 1970-2011 waves of the Panel Study of Income Dynamics merged with census data on respondents' neighborhoods, this study estimates a series of race-specific discrete-time marginal structural logit models for the risk of smoking initiation as a function of neighborhood poverty, as well as individual and household characteristics, from ages four through 25. Neighborhood selection bias is addressed using inverse-probability-of-treatment weights. Results indicate that more prolonged exposure to high (>20%) as opposed to low (<10%) poverty neighborhoods is associated with an increased risk of smoking onset by age 25, although consistent with prior literature, this effect is only evident among white and not nonwhite youth and young adults.

  11. ISSUES AND CHALLENGES IN MODELING CHILDREN'S LONGITUDINAL EXPOSURES: AN OZONE STUDY

    EPA Science Inventory

    Modeling children's exposures is a complicated, data-intensive process. Modeling longitudinal exposures, which are important for regulatory decision making, especially for most air toxics, adds another level of complexity and data requirements. Because it is difficult to model in...

  12. Effect and mechanism of waterborne prolonged Zn exposure influencing hepatic lipid metabolism in javelin goby Synechogobius hasta.

    PubMed

    Huang, Chao; Luo, Zhi; Hogstrand, Christer; Chen, Feng; Shi, Xi; Chen, Qi-Liang; Song, Yu-Feng; Pan, Ya-Xiong

    2016-07-01

    The present study was conducted to determine the effect and mechanism of waterborne Zn exposure influencing hepatic lipid deposition and metabolism in javelin goby Synechogobius hasta. S. hasta were exposed to four waterborne Zn concentrations (Zn 0.005 [control], 0.18, 0.36 and 0.55 mg l(-1) , respectively) for 60 days. Sampling occurred at days 20, 40 and 60, respectively. Zn exposure increased Zn content, declined hepatic lipid content and reduced viscerosomatic and hepatosomatic indices and lipogenic enzyme activities, including 6-phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and fatty acid synthase (FAS). At days 20 and 60, Zn exposure decreased hepatic mRNA levels of 6PGD, G6PD, ME, FAS, acetyl-CoA carboxylase (ACC)α, ACCβ, hormone-sensitive lipase (HSL)a, HSLb, sterol-regulator element-binding protein (SREBP)-1, peroxisome proliferators-activated receptor (PPAR)α and PPARγ. However, the mRNA levels of CPT 1 and adipose triglyceride lipase increased following Zn exposure. On day 40, Zn exposure reduced hepatic mRNA expression of 6PGD, G6PD, ME, FAS, ACCα, ACCβ, HSLa, HSLb, SREBP-1 and PPARγ but increased mRNA expression of CPT 1, adipose triglyceride lipase and PPARα. General speaking, Zn exposure reduced hepatic lipid content by inhibiting lipogenesis and stimulating lipolysis. For the first time, the present study provided evidence that chronic Zn exposure differentially influenced mRNA expression and activities of genes and enzymes involved in lipogenic and lipolytic metabolism in a duration-dependent manner, and provided new insight into the relationship between metal elements and lipid metabolism. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26602879

  13. Acute Ozone (O3) Exposure Accelerates Diet-Induced Pulmonary Injury and Metabolic Alterations in a Rat Model of Type II Diabetes

    EPA Science Inventory

    Abstract for Society of Toxicology, March 22-25, 2015, San Diego, CAAcute Ozone (O3) Exposure Accelerates Diet-Induced Pulmonary Injury and Metabolic Alterations in a Rat Model of Type II DiabetesS.J. Snow1,3, D. Miller2, V. Bass2, M. Schladweiler3, A. Ledbetter3, J. Richards3, C...

  14. [Variability of DNA simple sequence repeats in peripheral blood of humans subjected to prolonged exposures of ionizing radiation].

    PubMed

    Lomaeva, M G; Malakhova, L V; Zakharova, M L; Sokolova, S N; Fomenko, L A; Antipova, V N; Soboleva, I Iu; Bezlepkin, V G; Kirillova, E N; Gaziev, A I

    2013-01-01

    Long-term post-radiation changes in the level of microsatellite DNA polymorphism in peripheral blood of the male "Mayak" employees (Ozyorsk, Russia), who had been exposed to prolonged gamma-irradiation during professional activities, were studied. DNA samples were obtained from the Radiobiology Repository of Human Tissue (Southern-Urals Biophysics Institute FMBA) and used as templates for arbitrarily primed PCR. Comparative analysis of the obtained samples of DNA fragments showed a significant increase in the number of high-molecular fragments and reduction in the number of amplified low molecular weight DNA fragments in comparison with the control. However, a direct correlation of the level of DNA polymorphism with the accumulated total dose of radiation was not found. The study of the polymorphism of microsatellite DNA repeats can be used for qualitative assessment of the levels of genetic variability.

  15. Visible leaf injury in young trees of Fagus sylvatica L. and Quercus robur L. in relation to ozone uptake and ozone exposure. An Open-Top Chambers experiment in South Alpine environmental conditions.

    PubMed

    Gerosa, G; Marzuoli, R; Desotgiu, R; Bussotti, F; Ballarin-Denti, A

    2008-03-01

    An Open-Top Chambers experiment on Fagus sylvatica and Quercus robur seedlings was conducted in order to compare the performance of an exposure-based (AOT40) and a flux-based approaches in predicting the appearance of ozone visible injuries on leaves. Three different ozone treatments (charcoal-filtered; non-filtered; and open plots) and two soil moisture treatments (watered and non-watered plots) were performed. A Jarvisian stomatal conductance model was drawn up and parameterised for both species and typical South Alpine environmental conditions, thus allowing the calculation of ozone stomatal fluxes for every treatment. A critical ozone flux level for the onset of leaf visible injury in beech was clearly identified between 32.6 and 33.6 mmolO3 m(-2). In contrast, it was not possible to identify an exposure critical level using the AOT40 index. Water stress delayed the onset of the leaf visible injuries, but the flux-based approach was able to take it into account accurately.

  16. Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells.

    PubMed

    Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

    2015-10-01

    Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE.

  17. Use of branch and whole tree exposure systems to evaluate ozone impacts on forest trees

    SciTech Connect

    Schaap, W.

    1992-01-01

    An integrated research program was carried out to study the effects of ozone on physiological processes and growth of field-grown Douglas-fir saplings over a two year period (1989-1990). The main objective was to evaluate the use of branches as a means of scaling in air pollution research with a test of the hypothesis that branches can be treated as functionally independent units. This program was unique for a number of reasons, including (a) using >3.5 m tall saplings as opposed to seedlings and (b) experimentally separating the response of the whole tree from its parts (i.e. branches).

  18. Ozone exposure alters temporal fluctuations of sup 14 C-labeled assimilate pools in leaves of Pinus taeda L

    SciTech Connect

    Friend, A.L. ); Tomlinson, P.T. )

    1991-05-01

    The effects of O{sub 3} on uptake and distribution of {sup 14}C within current-year foliage of 3-year-old loblolly pine (Pinus taeda L.) seedlings were studied using open-top exposure chambers that delivered ozone at three concentrations: sub-ambient O{sub 3} (charcoal-filtered air (CF)); ambient O{sub 3}(AMB); and twice-ambient O{sub 3} (2X). Seedlings were exposed to O{sub 3} from May to Oct. of 1987, 1988, and 1989. In July, Aug., and Sept. 1989, individual foliage fascicles were labeled with {sup 14}CO{sub 2}; harvested at 0, 0.5, 4, 24, and 48h after labeling; and analyzed for {sup 14}C in lipids and pigments, protein, starch, residue, sugars, organic acids, and amino acids. O{sub 3} affected initial (0 h) incorporation of {sup 14}C into different chemical fractions, and the relative distribution of {sup 14}C among fractions at specific points in time. Starch dynamics were particularly responsive to and negatively affected by O{sub 3}. In 2X treatments, only 39-46% of the initial (0 h) {sup 14}C incorporated into starch remained after 48h, compared with a range of 56-90% remaining in CF treatments. The percentage of {sup 14}C in the starch fraction after 48 h decreased by nearly three-fold in August from CF to 2X treatments (%total {sup 14}C in starch: 31% (CF), 17% (AMB), and 11% (2X)). The authors data indicated that foliar starch synthesis and/or retention was depressed by ozone exposure during late-season months, and supported the concept that O{sub 3} decreases growth by depleting carbohydrate reserves. Other findings will be discussed.

  19. Rat lung benzo(a)pyrene metabolism following three days continuous exposure to 0. 6 ppm ozone

    SciTech Connect

    Bassett, D.J.; Bowen-Kelly, E.; Seed, J.L.

    1988-06-01

    Changes in the extent and pattern of benzo(a)pyrene metabolism were investigated in lungs isolated from rats following ozone exposures that are associated with the proliferation of alveolar and bronchiolar epithelia. Radiolabel incorporation into metabolic products were determined at the end of 60 min perfusions with 50-55 nmol of (6-3H) (7, 10-14C) benzo(a)pyrene (BaP), which in unexposed lungs resulted in a total BaP utilization of 0.77 +/- 0.05 nmol (14C) BaP/h/lung, recovered bound to tissue macromolecules (12%), as tissue and perfusate ethyl acetate-soluble products (59%), and as perfusate water-soluble conjugates (29%). Total metabolism at the sixth position of the BaP molecule was indicated by a 3H2O production of 0.07 +/- 0.01 nmol BaP/h per lung, that resulted in the formation of quinones (33%), acid-hydrolysable (40%) and acid-resistant (27%) water-soluble products, indicated by 14C- minus 3H-labelling. Ozone-exposed lungs demonstrated an increased total (14C) BaP utilization to 3.05 +/- 0.05 nmol/h/lung. Although BaP metabolism to all products was increased, the proportion of metabolism involving the 6th position was enhanced from 10% to 25% of total BaP utilization, which was accounted for by relative increases in tissue retained quinones and in perfusate acid-hydrolysable conjugates. These data demonstrated that quinone formation represents a major pathway of lung polycyclic aromatic hydrocarbon metabolism that is greatly enhanced in lungs with proliferating epithelia associated with oxidant exposure.

  20. Role of surfactant protein-A (SP-A) in lung injury in response to acute ozone exposure of SP-A deficient mice

    SciTech Connect

    Haque, Rizwanul; Umstead, Todd M.; Ponnuru, Padmavathi; Guo Xiaoxuan; Hawgood, Samuel; Phelps, David S.; Floros, Joanna . E-mail: jfloros@psu.edu

    2007-04-01

    Millions are exposed to ozone levels above recommended limits, impairing lung function, causing epithelial damage and inflammation, and predisposing some individuals to pneumonia, asthma, and other lung conditions. Surfactant protein-A (SP-A) plays a role in host defense, the regulation of inflammation, and repair of tissue damage. We tested the hypothesis that the lungs of SP-A(-/-) (KO) mice are more susceptible to ozone-induced damage. We compared the effects of ozone on KO and wild type (WT) mice on the C57BL/6 genetic background by exposing them to 2 parts/million of ozone for 3 or 6 h and sacrificing them 0, 4, and 24 h later. Lungs were subject to bronchoalveolar lavage (BAL) or used to measure endpoints of oxidative stress and inflammation. Despite more total protein in BAL of KO mice after a 3 h ozone exposure, WT mice had increased oxidation of protein and had oxidized SP-A dimers. In KO mice there was epithelial damage as assessed by increased LDH activity and there was increased phospholipid content. In WT mice there were more BAL PMNs and elevated macrophage inflammatory protein (MIP)-2 and monocyte chemoattractant protein (MCP)-1. Changes in MIP-2 and MCP-1 were observed in both KO and WT, however mRNA levels differed. In KO mice MIP-2 mRNA levels changed little with ozone, but in WT levels they were significantly increased. In summary, several aspects of the inflammatory response differ between WT and KO mice. These in vivo findings appear to implicate SP-A in regulating inflammation and limiting epithelial damage in response to ozone exposure.

  1. Prolonged inorganic arsenite exposure suppresses insulin-stimulated AKT S473 phosphorylation and glucose uptake in 3T3-L1 adipocytes: Involvement of the adaptive antioxidant response

    SciTech Connect

    Xue, Peng; Hou, Yongyong; Zhang, Qiang; Woods, Courtney G.; Yarborough, Kathy; Liu, Huiyu; Sun, Guifan; Andersen, Melvin E.; Pi, Jingbo

    2011-04-08

    Highlights: {yields} In 3T3-L1 adipocytes iAs{sup 3+} decreases insulin-stimulated glucose uptake. {yields} iAs{sup 3+} attenuates insulin-induced phosphorylation of AKT S473. {yields} iAs{sup 3+} activates the cellular adaptive oxidative stress response. {yields} iAs{sup 3+} impairs insulin-stimulated ROS signaling. {yields} iAs{sup 3+} decreases expression of adipogenic genes and GLUT4. -- Abstract: There is growing evidence that chronic exposure of humans to inorganic arsenic, a potent environmental oxidative stressor, is associated with the incidence of type 2 diabetes (T2D). One critical feature of T2D is insulin resistance in peripheral tissues, especially in mature adipocytes, the hallmark of which is decreased insulin-stimulated glucose uptake (ISGU). Despite the deleterious effects of reactive oxygen species (ROS), they have been recognized as a second messenger serving an intracellular signaling role for insulin action. Nuclear factor erythroid 2-related factor 2 (NRF2) is a central transcription factor regulating cellular adaptive response to oxidative stress. This study proposes that in response to arsenic exposure, the NRF2-mediated adaptive induction of endogenous antioxidant enzymes blunts insulin-stimulated ROS signaling and thus impairs ISGU. Exposure of differentiated 3T3-L1 cells to low-level (up to 2 {mu}M) inorganic arsenite (iAs{sup 3+}) led to decreased ISGU in a dose- and time-dependent manner. Concomitant to the impairment of ISGU, iAs{sup 3+} exposure significantly attenuated insulin-stimulated intracellular ROS accumulation and AKT S473 phosphorylation, which could be attributed to the activation of NRF2 and induction of a battery of endogenous antioxidant enzymes. In addition, prolonged iAs{sup 3+} exposure of 3T3-L1 adipocytes resulted in significant induction of inflammatory response genes and decreased expression of adipogenic genes and glucose transporter type 4 (GLUT4), suggesting chronic inflammation and reduction in GLUT4

  2. A transient increase in lipid peroxidation primes preadipocytes for delayed mitochondrial inner membrane permeabilization and ATP depletion during prolonged exposure to fatty acids

    PubMed Central

    Rogers, Carlyle; Davis, Barbara; Neufer, P. Darrell; Murphy, Michael P.; Anderson, Ethan J; Robidoux, Jacques

    2014-01-01

    Preadipocytes are periodically subjected to fatty acid (FA) concentrations that are potentially cytotoxic. We tested the hypothesis that prolonged exposure of preadipocytes of human origin to a physiologically relevant mix of FAs leads to mitochondrial inner membrane (MIM) permeabilization and ultimately to mitochondrial crisis. We found that exposure of preadipocytes to FAs led to progressive cyclosporin A-sensitive MIM permeabilization, which in turn caused reduction in MIM potential (ΔΨM), oxygen consumption, ATP synthetic capacity, and ultimately death. Additionally, we showed that FAs induce a transient increase in intramitochondrial ROS and lipid peroxide production lasting roughly 30 and 120 minutes for the ROS and lipid peroxides, respectively. MIM permeabilization and its deleterious consequences including mitochondrial crisis and cell death were prevented by treating the cells with the mitochondrial FA uptake inhibitor, Etomoxir; the mitochondrion selective superoxide and lipid peroxide antioxidants, MitoTempo and MitoQ; or the lipid peroxide and reactive carbonyl scavenger, L-carnosine. FAs also promoted a delayed oxidative stress phase. However, since the beneficial effects of Etomoxir, MitoTempo and L-carnosine were lost by delaying the treatment by 2 hours, it suggested that the initial phase was sufficient to prime the cells for the delayed MIM permeabilization and mitochondrial crisis. It also suggested that the second ROS production phase is a consequence of this loss in mitochondrial health. Altogether, our data suggest that approaches designed to diminish intramitochondrial ROS or lipid peroxide accumulation as well as MIM permeabilization, are valid mechanism-based therapeutic avenues to prevent the loss in preadipocyte metabolic fitness associated with prolonged exposure to elevated FA levels. PMID:24269897

  3. Influence of ozone and paracetic acid disinfection on adhesion of resilient liners to acrylic resin

    PubMed Central

    2016-01-01

    PURPOSE The aim of this study was to evaluate the effect of paracetic acid (PAA) and ozone disinfection on the tensile bond strength (TBS) of silicone-based resilient liners to acrylic resins. MATERIALS AND METHODS One hundred and twenty dumbbell shaped heat-polymerized acrylic resins were prepared. From the mid segment of the specimens, 3 mm of acrylic were grinded off and separated parts were reattached by resilient liners. The specimens were divided into 2 control (control1, control7) and 4 test groups of PAA and ozone disinfection (PAA1, PAA7, ozone1 and ozone7; n=10). While control groups were immersed in distilled water for 10 min (control1) and 7 days (control7), test groups were subjected to PAA (16 g/L) or ozone rich water (4 mg/L) for 1 cycle (10 min for PAA and 60 min for ozone) per day for 7 days prior to tensile tests. Measurements of the TBS were analyzed using 3-way ANOVA and Tukey's HSD test. RESULTS Adhesive strength of Mollosil decreased significantly by application of ozone disinfection. PAA disinfection had no negative effect on the TBS values of Mollosil and Molloplast B to acrylic resin. Single application of ozone disinfection did not have any negative effect on TBS values of Molloplast B, but prolonged exposure to ozone decreased its adhesive strength. CONCLUSION The adhesion of resilient liners to acrylic was not adversely affected by PAA disinfection. Immersion in ozonated water significantly decreased TBS of Mollosil. Prolonged exposure to ozone negatively affects adhesion of Molloplast B to denture base materials. PMID:27555898

  4. Association of short-term exposure to ground-level ozone and respiratory outpatient clinic visits in a rural location – Sublette County, Wyoming, 2008–2011

    SciTech Connect

    Pride, Kerry R.; Peel, Jennifer L.; Robinson, Byron F.; Busacker, Ashley; Grandpre, Joseph; Bisgard, Kristine M.; Yip, Fuyuen Y.; Murphy, Tracy D.

    2015-02-15

    Objective: Short-term exposure to ground-level ozone has been linked to adverse respiratory and other health effects; previous studies typically have focused on summer ground-level ozone in urban areas. During 2008–2011, Sublette County, Wyoming (population: ~10,000 persons), experienced periods of elevated ground-level ozone concentrations during the winter. This study sought to evaluate the association of daily ground-level ozone concentrations and health clinic visits for respiratory disease in this rural county. Methods: Clinic visits for respiratory disease were ascertained from electronic billing records of the two clinics in Sublette County for January 1, 2008–December 31, 2011. A time-stratified case-crossover design, adjusted for temperature and humidity, was used to investigate associations between ground-level ozone concentrations measured at one station and clinic visits for a respiratory health concern by using an unconstrained distributed lag of 0–3 days and single-day lags of 0 day, 1 day, 2 days, and 3 days. Results: The data set included 12,742 case-days and 43,285 selected control-days. The mean ground-level ozone observed was 47±8 ppb. The unconstrained distributed lag of 0–3 days was consistent with a null association (adjusted odds ratio [aOR]: 1.001; 95% confidence interval [CI]: 0.990–1.012); results for lags 0, 2, and 3 days were consistent with the null. However, the results for lag 1 were indicative of a positive association; for every 10-ppb increase in the 8-h maximum average ground-level ozone, a 3.0% increase in respiratory clinic visits the following day was observed (aOR: 1.031; 95% CI: 0.994–1.069). Season modified the adverse respiratory effects: ground-level ozone was significantly associated with respiratory clinic visits during the winter months. The patterns of results from all sensitivity analyzes were consistent with the a priori model. Conclusions: The results demonstrate an association of increasing ground

  5. Prolonged abstinence from developmental cocaine exposure dysregulates BDNF and its signaling network in the medial prefrontal cortex of adult rats.

    PubMed

    Giannotti, Giuseppe; Caffino, Lucia; Calabrese, Francesca; Racagni, Giorgio; Riva, Marco A; Fumagalli, Fabio

    2014-04-01

    Although evidence exists that chronic cocaine exposure during adulthood is associated with changes in BDNF expression, whether and how cocaine exposure during adolescence modulates BDNF is still unknown. To address this issue, we exposed rats to repeated cocaine injections from post-natal day (PD) 28 to PD 42, a period that roughly approximates adolescence in humans, and we carried out a detailed analysis of the BDNF system in the medial prefrontal cortex (mPFC) of rats sacrificed 3 d (PD 45) and 48 d (PD 90) after the last cocaine treatment. We found that developmental exposure to cocaine altered transcriptional and translational mechanisms governing neurotrophin expression. Total BDNF mRNA levels, in fact, were enhanced in the mPFC of PD 90 rats exposed to cocaine in adolescence, an effect sustained by changes in BDNF exon IV through the transcription factors CaRF and NF-kB. While a profound reduction of specific BDNF-related miRNAs (let7d, miR124 and miR132) may contribute to explaining the increased proBDNF levels, the up-regulation of the extracellular proteases tPA is indicative of increased processing leading to higher levels of released mBDNF. These changes were associated with increased activation of the trkB-Akt pathway resulting in enhanced pmTOR and pS6 kinase, which ultimately produced an up-regulation of Arc and a consequent reduction of GluA1 expression in the mPFC of PD 90 cocaine-treated rats. These findings demonstrate that developmental exposure to cocaine dynamically dysregulates BDNF and its signaling network in the mPFC of adult rats, providing novel mechanisms that may contribute to cocaine-induced changes in synaptic plasticity. PMID:24345425

  6. Prolonged abstinence from developmental cocaine exposure dysregulates BDNF and its signaling network in the medial prefrontal cortex of adult rats.

    PubMed

    Giannotti, Giuseppe; Caffino, Lucia; Calabrese, Francesca; Racagni, Giorgio; Riva, Marco A; Fumagalli, Fabio

    2014-04-01

    Although evidence exists that chronic cocaine exposure during adulthood is associated with changes in BDNF expression, whether and how cocaine exposure during adolescence modulates BDNF is still unknown. To address this issue, we exposed rats to repeated cocaine injections from post-natal day (PD) 28 to PD 42, a period that roughly approximates adolescence in humans, and we carried out a detailed analysis of the BDNF system in the medial prefrontal cortex (mPFC) of rats sacrificed 3 d (PD 45) and 48 d (PD 90) after the last cocaine treatment. We found that developmental exposure to cocaine altered transcriptional and translational mechanisms governing neurotrophin expression. Total BDNF mRNA levels, in fact, were enhanced in the mPFC of PD 90 rats exposed to cocaine in adolescence, an effect sustained by changes in BDNF exon IV through the transcription factors CaRF and NF-kB. While a profound reduction of specific BDNF-related miRNAs (let7d, miR124 and miR132) may contribute to explaining the increased proBDNF levels, the up-regulation of the extracellular proteases tPA is indicative of increased processing leading to higher levels of released mBDNF. These changes were associated with increased activation of the trkB-Akt pathway resulting in enhanced pmTOR and pS6 kinase, which ultimately produced an up-regulation of Arc and a consequent reduction of GluA1 expression in the mPFC of PD 90 cocaine-treated rats. These findings demonstrate that developmental exposure to cocaine dynamically dysregulates BDNF and its signaling network in the mPFC of adult rats, providing novel mechanisms that may contribute to cocaine-induced changes in synaptic plasticity.

  7. Prolonged Exposure to HIV Reinforces a Poised Epigenetic Program for PD-1 Expression in Virus-specific CD8 T Cells

    PubMed Central

    Youngblood, Ben; Noto, Alessandra; Porichis, Filippos; Akondy, Rama S.; Ndhlovu, Zaza M.; Austin, James W.; Bordi, Rebeka; Procopio, Francesco A.; Miura, Toshiyuki; Allen, Todd M.; Sidney, John; Sette, Alessandro; Walker, Bruce D.; Ahmed, Rafi; Boss, Jeremy M.; Sékaly, Rafick-Pierre; Kaufmann, Daniel E.

    2013-01-01

    Antigen-specific CD8 T cells play a critical role in controlling HIV infection but eventually lose antiviral functions in part because of expression and signaling through the inhibitory PD-1 receptor. To better understand the impact of prolonged TCR ligation on regulation of PD-1 expression in HIV-specific CD8 T cells we investigated the capacity of virus-specific CD8 T cells to modify the PD-1 epigenetic program following reduction in viral load. We observed that the transcriptional regulatory region was unmethylated in the PD-1hi HIV-specific CD8 T cells while it remained methylated in donor matched naïve cells at acute and chronic stages of infection. Surprisingly, the PD-1 promoter remained unmethylated in HIV-specific CD8 T cells from subjects with a viral load controlled by antiviral therapy for greater than 2 years or from elite controllers. Together these data demonstrate that the epigenetic program at the PD-1 locus becomes fixed following prolonged exposure to HIV virus. PMID:23772031

  8. Vitamin C, uric acid, and glutathione gradients in murine stratum corneum and their susceptibility to ozone exposure.

    PubMed

    Weber, S U; Thiele, J J; Cross, C E; Packer, L

    1999-12-01

    The stratum corneum has been recognized as the main cutaneous oxidation target of atmospheric ozone (O3), a major part of photochemical smog. This study reports the presence and distribution of vitamin C, glutathione, and uric acid in murine stratum corneum, and evaluates their susceptibility to acute environmental exposure to O3. Based on tape stripping and a modified extraction method with high performance liquid chromatography electrochemical analysis, we detected vitamin C (208.0 +/- 82.5 pmol per 10 consecutive pooled tapes), glutathione (283.7 +/-96.3), and uric acid (286.4 +/-47.1) in murine stratum corneum as compared with only 16.5 +/- 1.4 pmol alpha-tocopherol. Vitamin C, glutathione (both p < 00.001), and urate (p < 0.01) were found to exhibit a gradient with the lowest concentrations in the outer layers and a steep increase in the deeper layers. To investigate the effect of O3 exposure on hydrophilic antioxidants, we exposed SKH-1 hairless mice to O3 concentrations of 0, 0.8, 1, and 10 p.p.m., and stratum corneum was analyzed before and after exposure. Whereas mock exposure with 0 p.p. m. for 2 h had no significant effect, O3 doses of 1 p.p.m. for 2 h and above showed depletion of all three antioxidants. Vitamin C was decreased to 80% +/- 15% of its pretreatment content (p < 0.05), GSH to 41% +/- 24% (p < 0.01), and uric acid to 44% +/- 28% (p < 0.01). This report demonstrates the previously unrecognized role of hydrophilic antioxidants in the stratum corneum and provides further evidence that O3 induces oxidative stress in this outer skin layer.

  9. Biological effects of ozone

    SciTech Connect

    Lippmann, M. )

    1989-09-01

    Tropospheric ozone, a classic anthropogenic air pollutant, is going to remain a troublesome byproduct of contemporary civilization for many decades. We have known for some time that the hydrocarbons and nitrogen oxides from motor vehicles, together with actinic radiation, account for local and regional photochemistry leading to prolonged afternoon ozone peaks. We also now know that agricultural burning and intensive animal husbandry elevate regional and mesoscale concentrations of ozone and its precursors, and that remote background levels of ozone have been rising steadily throughout this century. The changes we will have to make in emission controls to appreciably reduce current tropospheric ozone levels will have profound effects on our transportation systems, consumer products, and lifestyles. As a society, we will have to make difficult choices about the levels of ozone-associated health, welfare, and natural system damage we will tolerate, or conversely, how much we are willing to pay for controls which can minimize the damage.

  10. Oxidative stress caused by ozone exposure induces β-amyloid 1-42 overproduction and mitochondrial accumulation by activating the amyloidogenic pathway.

    PubMed

    Hernández-Zimbrón, L F; Rivas-Arancibia, S

    2015-09-24

    Oxidative stress is a major risk factor for Alzheimer's disease (AD) that has been suggested to be the trigger of AD pathology. However, whether oxidative damage precedes and contributes directly to the intracellular accumulation of beta amyloid 1-42 (βA42) peptide remains a matter of debate. Chronic exposure to low doses of ozone similar to the levels during a day of high pollution in México City causes a state of oxidative stress that elicits progressive neurodegeneration in the hippocampi of rats. Several reports have demonstrated that the mitochondria are among the first organelles to be affected by oxidative stress and βA42 toxicity and act as sites of the accumulation of βA42, which affects energy metabolism. However, the mechanisms related to the neurodegeneration process and organelle damage that occur in conditions of chronic exposure to low doses of ozone have not been demonstrated. To analyze the effect of chronic ozone chronic exposure on changes in the production and accumulation of the βA42 and βA40 peptides in the mitochondria of hippocampal neurons of rats exposed to ozone, we examined the mitochondrial expression levels of Presenilins 1 and 2 and ADAM10 to detect changes related to the oxidative stress caused by low doses of ozone (0.25ppm). The results revealed significant accumulations of βA42 peptide in the mitochondrial fractions on days 60 and 90 of ozone exposure along with reductions in beta amyloid 1-40 accumulation, significant overexpressions of Pres2 and significant reductions in ADAM10 expression. Beta amyloid immunodetection revealed that there were some intracellular deposits of βA42 and that βA42 and the mitochondrial markers OPA1 and COX1 colocalized. These results indicate that the time of exposure to ozone and the accumulation of βA42 in the mitochondria of the hippocampal cells of rats were correlated. Our results suggest that the accumulation of the βA42 peptide may promote mitochondrial dysfunction due to its

  11. Oxidative stress caused by ozone exposure induces β-amyloid 1-42 overproduction and mitochondrial accumulation by activating the amyloidogenic pathway.

    PubMed

    Hernández-Zimbrón, L F; Rivas-Arancibia, S

    2015-09-24

    Oxidative stress is a major risk factor for Alzheimer's disease (AD) that has been suggested to be the trigger of AD pathology. However, whether oxidative damage precedes and contributes directly to the intracellular accumulation of beta amyloid 1-42 (βA42) peptide remains a matter of debate. Chronic exposure to low doses of ozone similar to the levels during a day of high pollution in México City causes a state of oxidative stress that elicits progressive neurodegeneration in the hippocampi of rats. Several reports have demonstrated that the mitochondria are among the first organelles to be affected by oxidative stress and βA42 toxicity and act as sites of the accumulation of βA42, which affects energy metabolism. However, the mechanisms related to the neurodegeneration process and organelle damage that occur in conditions of chronic exposure to low doses of ozone have not been demonstrated. To analyze the effect of chronic ozone chronic exposure on changes in the production and accumulation of the βA42 and βA40 peptides in the mitochondria of hippocampal neurons of rats exposed to ozone, we examined the mitochondrial expression levels of Presenilins 1 and 2 and ADAM10 to detect changes related to the oxidative stress caused by low doses of ozone (0.25ppm). The results revealed significant accumulations of βA42 peptide in the mitochondrial fractions on days 60 and 90 of ozone exposure along with reductions in beta amyloid 1-40 accumulation, significant overexpressions of Pres2 and significant reductions in ADAM10 expression. Beta amyloid immunodetection revealed that there were some intracellular deposits of βA42 and that βA42 and the mitochondrial markers OPA1 and COX1 colocalized. These results indicate that the time of exposure to ozone and the accumulation of βA42 in the mitochondria of the hippocampal cells of rats were correlated. Our results suggest that the accumulation of the βA42 peptide may promote mitochondrial dysfunction due to its

  12. Impaired exercise performance and pulmonary function in elite cyclists during low-level ozone exposure in a hot environment

    SciTech Connect

    Gong, H. Jr.; Bradley, P.W.; Simmons, M.S.; Tashkin, D.P.

    1986-10-01

    We evaluated the effects of low concentrations of ozone on the exercise performance and pulmonary function of 17 top-caliber endurance cyclists under conditions simulating competition and realistic temperature (3/sup 0/C). Each subject was randomly exposed to filtered air (FA), 0.12 and 0.20 ppm O/sub 3/ on separate days in an environmental chamber. Each subject attempted to maintain submaximal exercise on a cycle ergometer equivalent to approximately 70% of maximal oxygen consumption (VO/sub 2/max) for 60 min, followed by incremented (maximal) exercise until exhaustion. During submaximal exercise, average minute ventilation (VE) (89 L/min), VO/sub 2/ (51 ml/min/kg or 72% VO/sub 2/max), work load (260 W), and work time (57 min) were similar across all exposures. During maximal exercise, average peak VE (150 L/min), VO/sub 2/ (68 ml/min/kg), work load (382 W), and ride time (263 s) were similar between 0.12 ppm O/sub 3/ and FA. However, significant reductions in peak VE (18%), VO/sub 2/ (16%), tidal volume (22%), work load (8%), and ride time (30%) occurred in 0.20 ppm O/sub 3/ compared with those in FA. Postexercise decrements in forced expired volume in one second (FEV1) averaged 5.6% and 21.6% in 0.12 and 0.20 ppm O/sub 3/, respectively. Ozone-related symptoms were mild in 0.12 ppm O/sub 3/ but intensified and probably limited maximal performance in 13 subjects in 0.20 ppm O/sub 3/. Changes in carbon monoxide diffusing capacity (adjusted for alveolar volume) were not significant across exposures. Nine subjects showed histamine hyperresponsiveness (i.e., greater than 20% decrease from the control postdiluent FEV1) after exposure to 0.20 ppm O/sub 3/ as compared with 1 subject in 0.12 ppm O/sub 3/.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Clinical and pathological manifestations of cardiovascular disease in rat models: the influence of acute ozone exposure

    EPA Science Inventory

    This paper shows that rat models of cardiovascular diseases have differential degrees of underlying pathologies at a young age. Rodent models of cardiovascular diseases (CVD) and metabolic disorders are used for examining susceptibility variations to environmental exposures. How...

  14. Effect of chronic exposure to ozone and nitric acid on cytochrome P450 monooxygenase system of rat lung and liver

    SciTech Connect

    Sindhu, R.K.; Mautz, W.J.; Ichiro Fujita, Nai-San Wang; Yutaka, Kikkawa

    1996-03-08

    Male F344/N rats were exposed to 0.15ppm ozone (O{sub 3}) and 50{mu}g/m{sup 3} nitric acid (HNO{sub 3}) vapor alone and in combination for 4h/day 3days/week for a total of 40 weeks. Exposure to HNO{sub 3} vapor alone caused a significant increase of 7-ethoxyresorufin O-deethylase (EROD) activity in the hepatic microsomes (p{le}0.05). Monoclonal cytochrome P450 aA1/1A2 antibody-precipitable EROD activity in the hepatic microsomes was increased by 59% (p{le}0.01) and 40T (p{le}0.05), respectively, in the HNO{sub 3} vapor and {sub 3}+HNO{sub 3} vapor groups. In the pulmonary microsomes, benzphetamine N-demethylase (BPND) activity was increased by 72% (p{le}0.01), 85% (p{le}0.01) and decreased by 15% (p{le}0.01), respectively, by exposure to O{sub 3}, O{sub 3}+HNO{sub 3} and HNO{sub 3} vapor, but was unaffected in the hepatic microsomes.

  15. Influence of ozone-exposure dynamics on the growth and yield of kidney bean (journal version)

    SciTech Connect

    Kohut, R.J.; Laurence, J.A.; Colavito, L.J.

    1988-01-01

    A field experiment was conducted in open-top chambers to assess the importance of peak exposure concentration and exposure frequency on the responses of kidney bean plants to O/sub 3/. There were five treatments in the study: charcoal-filtered air, constant exposure to 0.05 ppm O/sub 3/ (131 micrograms/cu m) daily, fluctuating exposure to 0.08 ppm O/sub 3/ on three alternate days, cluster exposure to 0.08 ppm O/sub 3/ on three consecutive days, and peak exposure to 0.12 ppm O/sub 3/ on two consecutive days. There were no significant effects of the O/sub 3/-addition treatments on yield when compared to the plants receiving charcoal-filtered air. This indicates that there were no cumulative impacts on plants exposed to 0.12 ppm O/sub 3/ for 4h on two consecutive days followed by filtered air compared to plants receiving charcoal-filtered air. The seasonal 7-h average concentrations of O/sub 3/ in the peak and filtered-air treatments were approximately 0.040 and 0.025 ppm, respectively.

  16. Pulmonary Responses in Healthy Young Adults Exposed to Low Concentration of Ozone for 6.6 Hours with Mild Exercise

    EPA Science Inventory

    Rational: Recent studies have shown small but significant decreases in lung function following a prolonged exposure (6.6 hour) of healthy young adults to levels of ozone (0.08 ppm) near the current 8 hour standard. It is unclear, however, if such effects may be extended to concen...

  17. Effects of single- and multiday ozone exposures on respiratory function in active normal children

    SciTech Connect

    Spektor, D.M.; Thurston, G.D.; Mao, J.; He, D.; Hayes, C.; Lippmann, M. )

    1991-08-01

    Ventilatory function was measured twice daily on 46 healthy children aged 8-14 years on at least 7 days for each child during a 4-week period at a northwestern New Jersey residential summer camp in 1988. The highest 1-hr O3 concentration was 150 ppb, while the highest 12-hr H+ concentration (as H2SO4) was 18.6 micrograms/m3. The highest temperature-humidity index was 81 degrees F. The regressions of FVC, FEV1, FEF25-75, and PEFR on O3 in the hour preceding the afternoon function measurements yielded slopes essentially the same as those measured on other children at the same camp in 1984. Regressions of the changes in function between the late morning and late afternoon function measurements on average O3 concentration between them produced significant, but somewhat smaller effects, while regressions of morning function on O3 during the previous day indicated small but still significant effects. There were no significant correlations with other measured environmental variables including H+. Based on the results of this study and similar previous studies, we conclude that O3 exposures in ambient air produce greater lung function deficits in active young people in natural settings then does pure O3 in controlled chamber exposure studies because of: (1) longer exposures; (2) potentiation by other factors in the ambient exposures; (3) the persistence of effects from prior day's exposures; and (4) the persistence of a transient response associated with the daily peak of exposure. It follows that projections of likely effects in the real world from controlled chamber exposure studies should either have a large margin of safety, or the judgment of the extent of effects likely to occur among populations should be based directly on the effects observed in field studies.

  18. Inulin Supplementation Lowered the Metabolic Defects of Prolonged Exposure to Chlorpyrifos from Gestation to Young Adult Stage in Offspring Rats

    PubMed Central

    Reygner, Julie; Lichtenberger, Lydia; Elmhiri, Ghada; Dou, Samir; Bahi-Jaber, Narges; Rhazi, Larbi; Depeint, Flore; Bach, Veronique

    2016-01-01

    Increasing evidence indicates that chlorpyrifos (CPF), an organophosphorus insecticide, is involved in metabolic disorders. We assess the hypothesis whether supplementation with prebiotics from gestation to adulthood, through a modulation of microbiota composition and fermentative activity, alleviates CPF induced metabolic disorders of 60 days old offspring. 5 groups of Wistar rats, from gestation until weaning, received two doses of CPF pesticide: 1 mg/kg/day (CPF1) or 3.5 mg/kg/day (CPF3.5) with free access to inulin (10g/L in drinking water). Then male pups received the same treatment as dams. Metabolic profile, leptin sensitivity, insulin receptor (IR) expression in liver, gut microbiota composition and short chain fatty acid composition (SCFAs) in the colon, were analyzed at postnatal day 60 in the offspring (PND 60). CPF3.5 increased offspring’s birth body weight (BW) but decreased BW at PND60. Inulin supplementation restored the BW at PND 60 to control levels. Hyperinsulinemia and decrease in insulin receptor β in liver were seen in CPF1 exposed rats. In contrast, hyperglycemia and decrease in insulin level were found in CPF3.5 rats. Inulin restored the levels of some metabolic parameters in CPF groups to ranges comparable with the controls. The total bacterial population, short chain fatty acid (SCFA) production and butyrate levels were enhanced in CPF groups receiving inulin. Our data indicate that developmental exposure to CPF interferes with metabolism with dose related effects evident at adulthood. By modulating microbiota population and fermentative activity, inulin corrected adult metabolic disorders of rats exposed to CPF during development. Prebiotics supply may be thus considered as a novel nutritional strategy to counteract insulin resistance and diabetes induced by a continuous pesticide exposure. PMID:27760213

  19. Using air quality modeling to study source-receptor relationships between nitrogen oxides emissions and ozone exposures over the United States.

    PubMed

    Tong, Daniel Q; Muller, Nicholas Z; Kan, Haidong; Mendelsohn, Robert O

    2009-11-01

    Human exposure to ambient ozone (O(3)) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source-receptor relationships between nitrogen oxides (NO(x)) emissions and population exposure to ambient O(3) in 48 states over the continental United States. By removing NO(x) emissions from each state one at a time, we calculate the change in O(3) exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source-receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NO(x) emissions from upwind states contribute more to O(3) exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O(3) exposures in 90% of U.S. states. A state's NO(x) emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O(3) exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O(3) exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NO(x) is equal. In this study, the average O(3) exposures caused by one ton of NO(x) emissions ranges from -2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NO(x) emissions varies considerably over space.

  20. Using air quality modeling to study source-receptor relationships between nitrogen oxides emissions and ozone exposures over the United States.

    PubMed

    Tong, Daniel Q; Muller, Nicholas Z; Kan, Haidong; Mendelsohn, Robert O

    2009-11-01

    Human exposure to ambient ozone (O(3)) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source-receptor relationships between nitrogen oxides (NO(x)) emissions and population exposure to ambient O(3) in 48 states over the continental United States. By removing NO(x) emissions from each state one at a time, we calculate the change in O(3) exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source-receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NO(x) emissions from upwind states contribute more to O(3) exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O(3) exposures in 90% of U.S. states. A state's NO(x) emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O(3) exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O(3) exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NO(x) is equal. In this study, the average O(3) exposures caused by one ton of NO(x) emissions ranges from -2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NO(x) emissions varies considerably over space. PMID:19656569

  1. Increased vitamin E content in the lung after ozone exposure: A possible mobilization in response to oxidative stress

    SciTech Connect

    Elsayed, N.M.; Mustafa, M.G.; Mead, J.F. )

    1990-11-01

    Vitamin E (vE) is a biological free radical scavenger capable of providing antioxidant protection depending upon its tissue content. In previous studies, we observed that vE increased significantly in rat lungs after oxidant exposure, and we postulated that vE may be mobilized to the lung from other body sites under oxidative stress. To test this hypothesis, we fed Long-Evans rats either a vE-supplemented or a vE-deficient diet, injected them intraperitoneally with 14C-labeled vE, and then exposed half of each group to 0.5 ppm ozone (O3) for 5 days. After exposure, we determined vE content and label retention in lungs, liver, kidney, heart, brain, plasma, and white adipose tissue. Tissue vE content of all tissues generally reflected the dietary level, but labeled vE retention in all tissues was inversely related to tissue content, possibly reflecting a saturation of existing vE receptor sites in supplemented rats. Following O3 exposure, lung vE content increased significantly in supplemented rats and decreased in deficient rats, but the decrease was not statistically significant, and vE content remained unchanged in all other tissues of both dietary groups. Retention of 14C-labeled vE increased in all tissues of O3-exposed rats of both dietary groups, except in vE-deficient adipose tissue and vE-supplemented brain, where it decreased, and plasma, where it did not change. The marked increases in lung vE content and labeled vE retention of O3-exposed vE-supplemented rats support our hypothesis that vE may be mobilized to the lung in response to oxidative stress, providing that the vitamin is sufficiently available in other body sites.

  2. A Bayesian model for quantifying the change in mortality associated with future ozone exposures under climate change.

    PubMed

    Alexeeff, Stacey E; Pfister, Gabriele G; Nychka, Doug

    2016-03-01

    Climate change is expected to have many impacts on the environment, including changes in ozone concentrations at the surface level. A key public health concern is the potential increase in ozone-related summertime mortality if surface ozone concentrations rise in response to climate change. Although ozone formation depends partly on summertime weather, which exhibits considerable inter-annual variability, previous health impact studies have not incorporated the variability of ozone into their prediction models. A major source of uncertainty in the health impacts is the variability of the modeled ozone concentrations. We propose a Bayesian model and Monte Carlo estimation method for quantifying health effects of future ozone. An advantage of this approach is that we include the uncertainty in both the health effect association and the modeled ozone concentrations. Using our proposed approach, we quantify the expected change in ozone-related summertime mortality in the contiguous United States between 2000 and 2050 under a changing climate. The mortality estimates show regional patterns in the expected degree of impact. We also illustrate the results when using a common technique in previous work that averages ozone to reduce the size of the data, and contrast these findings with our own. Our analysis yields more realistic inferences, providing clearer interpretation for decision making regarding the impacts of climate change.

  3. Growth of radish and marigold following repeated exposure to nitrogen dioxide, sulfur dioxide, and ozone

    SciTech Connect

    Reinert, R.A.; Sanders, J.S.

    1982-02-01

    Radish and marigold plants were exposed to 0.3 ppM of nitrogen dioxide (NO/sub 2/), sulfur dioxide (SO/sub 2/), and /or ozone (O/sub 3/) nine times during a 3-wk period. No interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ were detected in measurement of radish foliage and root dry weight. Treatments containing O/sub 3/ reduced radish foliage and root (hypocotyl) dry weight 356 and 531 mg/plant, respectively. Interactions among NO/sub 2/, SO/sub 2/ and O/sub 3/ occurred in shoots and roots of marigold. SO/sub 2/ alone reduced marigold shoot and root dry weight, but this effect was reversed in the presence of O/sub 3/. The suppressive effect of SO/sub 2/ on root weight was also reversed by NO/sub 2/. Treatments containing SO/sub 2/ reduced dry flower weight 0.17 g/plant, but effects of the pollutant interactions observed in shoots and roots were not present. 8 references, 2 tables.

  4. Growth of radish and marigold following repeated exposure to nitrogen dioxide, sulfur dioxide, and ozone

    SciTech Connect

    Reinert, R.A.; Sanders, J.S.

    1982-02-01

    Radish and marigold plants were exposed to 0.3 ppm of nitrogen dioxide (NO/sub 2/), sulfur dioxide (SO/sub 2/), and/or ozone (O/sub 3/) nine times during a 3-wk period. No interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ were detected in measurement of radish foliage and root dry weight. Treatments containing O/sub 3/ reduced radish foliage and root (hypocotyl) dry weight 356 and 531 mg/plant, respectively. Interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ occurred in shoots and roots of marigold. SO/sub 2/ alone reduced marigold shoot and root dry weight, but this effect was reversed in the presence of O/sub 3/. The suppressive effect of SO/sub 2/ on root weight was also reversed by NO/sub 3/. Treatments containing SO/sub 2/ reduced dry flower weight 0.17 g/plant, but effects of the pollutant interactions observed in shoots and roots were not present.

  5. Effect of prolonged isothermal exposure on elevated-temperature, time-dependent fatigue-crack propagation in INCONEL alloy 783

    NASA Astrophysics Data System (ADS)

    Ma, Longzhou; Chang, Keh-Minn; Mannan, Sarwan K.; Patel, Shailesh J.

    2002-11-01

    The effect of isothermal exposure on the elevated-temperature, time-dependent fatigue-crack propagation (FCP) in INCONEL Alloy 783 is investigated. Commercially produced Alloy 783 was annealed and aged following the standard heat-treatment procedure. One set of specimens was then isothermally exposed at 500 °C for 3000 hours. All specimens were subjected to FCP tests with various hold-time periods and sustained-loading crack-growth tests at 538 °C and 650 °C in a laboratory-air environment. Without a hold time, the as-produced and isothermally exposed materials had comparable FCP rates at both test temperatures. With hold times of 100 and 300 seconds, the as-produced and isothermally exposed specimens had comparable FCP rates at 538 °C. Hold-time testing of the as-produced material at 650 °C showed abnormal time-dependent FCP and sustained-loading crack-growth retardation. However, hold-time testing of isothermally exposed material at 650 °C showed the steady sustained-loading crack growth and fully time-dependent FCP typically observed in many superalloys. Comparison with Alloy 718 data from the literature shows that FCP rates of as-produced Alloy 718 and isothermally exposed Alloy 783 are comparable at 650 °C. A fully time-dependent FCP model based on the damage-zone concept and a thermal-activation equation is proposed to characterize the FCP behaviors.

  6. Exposure assessment of air pollutants: a review on spatial heterogeneity and indoor/outdoor/personal exposure to suspended particulate matter, nitrogen dioxide and ozone

    NASA Astrophysics Data System (ADS)

    Monn, Christian

    This review describes databases of small-scale spatial variations and indoor, outdoor and personal measurements of air pollutants with the main focus on suspended particulate matter, and to a lesser extent, nitrogen dioxide and photochemical pollutants. The basic definitions and concepts of an exposure measurement are introduced as well as some study design considerations and implications of imprecise exposure measurements. Suspended particulate matter is complex with respect to particle size distributions, the chemical composition and its sources. With respect to small-scale spatial variations in urban areas, largest variations occur in the ultrafine (<0.1 μm) and the coarse mode (PM 10-2.5, resuspended dust). Secondary aerosols which contribute to the accumulation mode (0.1-2 μm) show quite homogenous spatial distribution. In general, small-scale spatial variations of PM 2.5 were described to be smaller than the spatial variations of PM 10. Recent studies in outdoor air show that ultrafine particle number counts have large spatial variations and that they are not well correlated to mass data. Sources of indoor particles are from outdoors and some specific indoor sources such as smoking and cooking for fine particles or moving of people (resuspension of dust) for coarse particles. The relationships between indoor, outdoor and personal levels are complex. The finer the particle size, the better becomes the correlation between indoor, outdoor and personal levels. Furthermore, correlations between these parameters are better in longitudinal analyses than in cross-sectional analyses. For NO 2 and O 3, the air chemistry is important. Both have considerable small-scale spatial variations within urban areas. In the absence of indoor sources such as gas appliances, NO 2 indoor/outdoor relationships are strong. For ozone, indoor levels are quite small. The study hypothesis largely determines the choice of a specific concept in exposure assessment, i.e. whether personal

  7. Foliar response of black cherry (Prunus serotina) clones to ambient ozone exposure in central Pennsylvania.

    PubMed

    Lee, J C; Skelly, J M; Steiner, K C; Zhang, J W; Savage, J E

    1999-06-01

    During late summer of 1996 and 1997 we examined ozone-induced foliar injury in a plantation of 111 black cherry trees (ramets) comprising 15 clones originating from wild ortets growing in the Allegheny National Forest, Pennsylvania, and the Monongahela National Forest, West Virginia. The experimental plantation was a clonal seed orchard in Centre County, Pennsylvania, started in 1971 using ortet buds grafted onto seedling rootstocks of mixed origin. Clones differed significantly in severity of foliar injury symptoms (F=31.83, p<0.001). One clone (R-12) had significantly more foliar injury with >50% leaf area affected than other clones during both years. In contrast, clone R-14, which is from the same area in northcentral Pennsylvania as R-12, exhibited significantly less injury (LAA<6%). Although ambient O(3) concentrations were similar in both years, foliar injury was significantly greater (15.7%) in 1996 than in 1997 (9.9%). This is probably explained by lower stomatal conductance in 1997 caused by drier and hotter weather patterns in June and July of that year. Despite very different weather patterns and overall levels of injury in 1996 and 1997, mean clonal injury was significantly correlated between both years of assessment (r=0.92, p<0.001). Within tree crowns, foliage in lower and inner crown positions was significantly more injured than foliage in upper and exterior crown positions. There was no evidence of geographically based population differences in sensitivity to foliar O(3) injury. On the contrary, results demonstrate that wild genotypes of proximal geographic origin may differ greatly in sensitivity. PMID:15093074

  8. Factors affecting stomatal uptake of ozone by different canopies and a comparison between dose and exposure.

    PubMed

    Zhang, Leiming; Vet, Robert; Brook, Jeffrey R; Legge, Allan H

    2006-10-15

    Measured ozone (O(3)) and carbon dioxide (CO(2)) concentrations and fluxes over five different canopies (mixed coniferous-deciduous forest, deciduous forest, corn, soybean and pasture) in the eastern USA were analyzed to investigate the stomatal uptake of O(3). It was found that the ambient O(3) concentration levels had little effect on stomatal conductance. However, the accumulated stomatal uptake of O(3), upon reaching a threshold value on any given day, appears to reduce the rate of further O(3) uptake substantially. This may explain why the maximum O(3) deposition velocity often appeared in the early morning hours over some forest canopies. Substantially reduced CO(2) fluxes over wet canopies compared to dry canopies suggest that stomata were likely partially or totally blocked by water droplets or films when canopies were wet. By using a big-leaf dry deposition model, measured O(3) fluxes were separated into stomatal and non-stomatal portions. It was estimated that stomatal uptake contributed 55-75% of the total daytime O(3) fluxes and 40-60% of the total daytime plus nighttime fluxes, depending on canopy type. This suggests that about half of the total O(3) flux occurred through the non-stomatal pathway. At three locations (deciduous forest, corn and soybean sites), O(3) concentrations of 30-60 ppb and of 60-85 ppb contributed equally to the accumulated stomatal fluxes, while at the other two locations (mixed coniferous-deciduous forest and pasture sites), concentrations of 30-60 ppb contributed twice as much as those from 60 to 85 ppb.

  9. Conservation of body calcium by increased dietary intake of potassium: A potential measure to reduce the osteoporosis process during prolonged exposure to microgravity

    NASA Technical Reports Server (NTRS)

    Nechay, Bohdan R.

    1989-01-01

    During the 1988 NASA Summer Faculty Fellowship Program, it was proposed that the loss of skeletal calcium upon prolonged exposure to microgravity could be explained, in part, by a renal maladjustment characterized by an increased urinary excretion of calcium. It was theorized that because the conservation of body fluids and electrolytes depends upon the energy of adenosine triphosphate and enzymes that control the use of its energy for renal ion transport, an induction of renal sodium and potassium-dependent adenosine triphosphatase (Na + K ATPase) by oral loading with potassium would increase the reabsorption of sodium directly and that of calcium indirectly, leading to improved hydration and to reduced calcium loss. Preliminary studies showed the following. Rats drinking water containing 0.2 M potassium chloride for six to 13 days excreted in urine 22 muEq of calcium and 135 muEq of sodium per 100 grams of body weight per day. The corresponding values for control rats drinking tap water were 43 muEq and 269 muEq respectively. Renal Na + K ATPase activity in potassium loaded rats was higher than in controls. Thus, oral potassium loading resulted in increased Na + K ATPase activity and diminished urinary excretion of calcium and of sodium as predicted by the hypothesis. An extension of these studies to humans has the potential of resulting in development of harmless, non-invasive, drug-free, convenient measures to reduce bone loss and other electrolyte and fluid problems in space travelers exposed to prolonged periods of microgravity.

  10. Beta-lactam antibiotic-induced platelet dysfunction: Evidence for irreversible inhibition of platelet activation in vitro and in vivo after prolonged exposure to penicillin

    SciTech Connect

    Burroughs, S.F.; Johnson, G.J. )

    1990-04-01

    beta-Lactam antibiotics cause platelet dysfunction with bleeding complications. Previous in vitro studies documented reversible inhibition of agonist-receptor interaction. This mechanism is inadequate to explain the effect of beta-lactam antibiotics in vivo. Platelet function does not return to normal immediately after drug treatment, implying irreversible inhibition of platelet function. We report here evidence of irreversible platelet functional and biochemical abnormalities after in vitro and in vivo exposure to beta-lactam antibiotics. Irreversible binding of (14C)-penicillin (Pen) occurred in vitro. After 24 hours' in vitro incubation with 10 to 20 mmol/L Pen, or ex vivo after antibiotic treatment, irreversible functional impairment occurred; but no irreversible inhibition of alpha 2 adrenergic receptors, measured with (3H)-yohimbine, or high-affinity thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptors, measured with agonist (3H)-U46619 and antagonist (3H)-SQ29548, occurred. However, low-affinity platelet TXA2/PGH2 receptors were decreased 40% after Pen exposure in vitro or in vivo, indicating irreversible membrane alteration. Two postreceptor biochemical events were irreversibly inhibited in platelets incubated with Pen for 24 hours in vitro or ex vivo after antibiotic treatment. Thromboxane synthesis was inhibited 28.3% to 81.7%. Agonist-induced rises in cytosolic calcium ((Ca2+)i) were inhibited 40.1% to 67.5% in vitro and 26.6% to 52.2% ex vivo. Therefore, Pen binds to platelets after prolonged exposure, resulting in irreversible dysfunction attributable to inhibition of TXA2 synthesis and impairment of the rise in (Ca2+)i. The loss of low-affinity TXA2/PGH2 receptors suggests that the primary site of action of these drugs is on the platelet membrane.

  11. Prolonged nicotine exposure down-regulates presynaptic NMDA receptors in dopaminergic terminals of the rat nucleus accumbens.

    PubMed

    Salamone, Alessia; Zappettini, Stefania; Grilli, Massimo; Olivero, Guendalina; Agostinho, Paula; Tomé, Angelo R; Chen, Jiayang; Pittaluga, Anna; Cunha, Rodrigo A; Marchi, Mario

    2014-04-01

    The presynaptic control of dopamine release in the nucleus accumbens (NAc) by glutamate and acetylcholine has a profound impact on reward signaling. Here we provide immunocytochemical and neurochemical evidence supporting the co-localization and functional interaction between nicotinic acetylcholine receptors (nAChRs) and N-methyl-D-aspartic acid (NMDA) receptors in dopaminergic terminals of the NAc. Most NAc dopaminergic terminals possessed the nAChR α4 subunit and the pre-exposure of synaptosomes to nicotine (30 μM) or to the α4β2-containing nAChR agonist 5IA85380 (10 nM) selectively inhibited the NMDA (100 μM)-evoked, but not the 4-aminopyridine (10 μM)-evoked, [(3)H] dopamine outflow; this inhibition was blunted by mecamylamine (10 μM). Nicotine and 5IA85380 pretreatment also inhibited the NMDA (100 μM)-evoked increase of calcium levels in single nerve terminals, an effect prevented by dihydro-β-erythroidine (1 μM). This supports a functional interaction between α4β2-containing nAChR and NMDA receptors within the same terminal, as supported by the immunocytochemical co-localization of α4 and GluN1 subunits in individual NAc dopaminergic terminals. The NMDA-evoked [(3)H]dopamine outflow was blocked by MK801 (1 μM) and inhibited by the selective GluN2B-selective antagonists ifenprodil (1 μM) and RO 25-6981 (1 μM), but not by the GluN2A-preferring antagonists CPP-19755 (1 μM) and ZnCl2 (1 nM). Notably, nicotine pretreatment significantly decreased the density of biotin-tagged GluN2B proteins in NAc synaptosomes. These results show that nAChRs dynamically and negatively regulate NMDA receptors in NAc dopaminergic terminals through the internalization of GluN2B receptors.

  12. Comparison of pulmonary biochemical effects of low-level ozone exposure on mice and rats.

    PubMed

    Mustafa, M G; Elsayed, N M; Quinn, C L; Postlethwait, E M; Gardner, D E; Graham, J A

    1982-01-01

    The biochemical effects of a 5-d continuous exposure to 0.45 ppm (882 microgram/m3) O3, were studied in the lungs of 2-mo-old male, specific-pathogen-free mice (Swiss Webster) and three strains of rats (Long-Evans, Wistar, and Sprague-Dawley). The results, expressed per lung, indicated a general increase in lung weight, DNA and protein contents, oxygen consumption, sulfhydryl metabolism, and the activities of several NADP+-reducing enzymes for all exposed animals relative to their controls. When the increases in the two species (mice versus three strains of rats) were compared, the mice showed significantly higher increases than the rats in several parameters. The responses among the three strains of rats were variable, but the differences were not significant. These observations suggest that Swiss Webster mice may offer a more sensitive animal model than rats for studying the pulmonary effects of a given low-level O3 exposure.

  13. The effect of ozone exposure on rat alveolar macrophage arachidonic acid metabolism

    SciTech Connect

    Madden, M.C.; Eling, T.E.; Dailey, L.A.; Friedman, M. )

    1991-01-01

    Rat alveolar macrophages were prelabeled with {sup 3}H-arachidonic acid ({sup 3}H-AA) and exposed to air or O3 (0.1-1.0 ppm) in vitro for 2 h. Alveolar macrophages released 3.6-fold more tritium at the 1.0 ppm exposure concentration compared with air-exposed macrophages. A significantly increased production of several {sup 3}H-AA metabolites, including 6-keto-PGF1 alpha, thromboxane B2, 12-hydroxy-5,8,10-heptadecatrienoic acid, prostaglandins E2 and D2, leukotrienes B4 and D4, and 15-hydroxyeicosatetraenoic acid was formed by macrophages exposed to 1.0 ppm O3 compared with air-exposed macrophages as determined by high performance liquid chromatography (HPLC) analysis. O3 exposure did not alter macrophage {sup 3}H-AA metabolism in response to calcium ionophore A23187. The largest tritiated peak observed in the HPLC chromatograms of O{sub 3}-exposed cells was a polar complex of products that contained various phospholipids and neutral lipids (including diacylglycerol) and possibly degradation products of {sup 3}H-AA and some of its metabolites. These changes in macrophage arachidonic acid metabolism may play an important role in the lung response to O{sub 3} exposure in vivo.

  14. Effects of long-term ambient ozone exposure on biomass and wood traits in poplar treated with ethylenediurea (EDU).

    PubMed

    Carriero, G; Emiliani, G; Giovannelli, A; Hoshika, Y; Manning, W J; Traversi, M L; Paoletti, E

    2015-11-01

    This is the longest continuous experiment where ethylenediurea (EDU) was used to protect plants from ozone (O3). Effects of long-term ambient O3 exposure (23 ppm h AOT40) on biomass of an O3 sensitive poplar clone (Oxford) were examined after six years from in-ground planting. Trees were irrigated with either water or 450 ppm EDU. Above (-51%) and below-ground biomass (-47%) was reduced by O3 although the effect was significant only for stem and coarse roots. Ambient O3 decreased diameter of the lower stem, and increased moisture content along the stem of not-protected plants (+16%). No other change in the physical wood structure was observed. A comparison with a previous assessment in the same experiment suggested that O3 effects on biomass partitioning to above-ground organs depend on the tree ontogenetic stage. The root/shoot ratios did not change, suggesting that previous short-term observations of reduced allocation to tree roots may be overestimated. PMID:26310976

  15. Effects of long-term ambient ozone exposure on biomass and wood traits in poplar treated with ethylenediurea (EDU).

    PubMed

    Carriero, G; Emiliani, G; Giovannelli, A; Hoshika, Y; Manning, W J; Traversi, M L; Paoletti, E

    2015-11-01

    This is the longest continuous experiment where ethylenediurea (EDU) was used to protect plants from ozone (O3). Effects of long-term ambient O3 exposure (23 ppm h AOT40) on biomass of an O3 sensitive poplar clone (Oxford) were examined after six years from in-ground planting. Trees were irrigated with either water or 450 ppm EDU. Above (-51%) and below-ground biomass (-47%) was reduced by O3 although the effect was significant only for stem and coarse roots. Ambient O3 decreased diameter of the lower stem, and increased moisture content along the stem of not-protected plants (+16%). No other change in the physical wood structure was observed. A comparison with a previous assessment in the same experiment suggested that O3 effects on biomass partitioning to above-ground organs depend on the tree ontogenetic stage. The root/shoot ratios did not change, suggesting that previous short-term observations of reduced allocation to tree roots may be overestimated.

  16. The impact of prolonged exposure on PTSD symptoms and associated psychopathology in people living with HIV: a randomized test of concept.

    PubMed

    Pacella, Maria L; Armelie, Aaron; Boarts, Jessica; Wagner, Glenn; Jones, Tracy; Feeny, Norah; Delahanty, Douglas L

    2012-07-01

    People living with HIV (PLWH) report elevated levels of posttraumatic stress disorder symptoms (PTSS) and associated comorbidities. The present study tested the efficacy of prolonged exposure (PE) at reducing PTSS, depression, negative posttraumatic cognitions, and substance use in PLWH. Participants were randomly assigned to receive PE (n = 40) or to a weekly monitoring control group (n = 25). Assessments occurred at baseline, post-intervention and 3-months post-treatment. Following the 3-month assessment, controls were offered the intervention. All PE recipients (whether originally from the PE or control group) completed a 6-month assessment. Intent-to-treat mixed model repeated measures ANOVAs were conducted through 3-months post-treatment; within group analyses were conducted through 6-months. PE recipients reported fewer PTSS and negative posttraumatic cognitions and were more likely to achieve good end-state functioning; gains were maintained at 6-months. No between-group differences emerged for substance use. Overall, results support the efficacy of PE in PLWH.

  17. Treating PTSD in Suicidal and Self-injuring Women with Borderline Personality Disorder: Development and Preliminary Evaluation of a Dialectical Behavior Therapy Prolonged Exposure Protocol

    PubMed Central

    Harned, Melanie S.; Korslund, Kathryn E.; Foa, Edna B.; Linehan, Marsha M.

    2012-01-01

    This study focused on the development and pilot testing of a protocol based on Prolonged Exposure (PE) that can be added to Dialectical Behavior Therapy (DBT) to treat PTSD in suicidal and self-injuring individuals with borderline personality disorder (BPD). Women with BPD, PTSD, and recent and/or imminent serious intentional self-injury (n=13) received one year of DBT with the DBT PE Protocol, plus three months of follow up assessment. The treatment was associated with significant reductions in PTSD, with the majority of patients no longer meeting criteria for PTSD at post-treatment (71.4% of DBT PE Protocol completers, 60.0% of the intent-to-treat sample). A minority of patients (27.3%) engaged in intentional self-injury during the study. Improvements were also found for suicidal ideation, dissociation, trauma-related guilt cognitions, shame, anxiety, depression, and social adjustment. There was no evidence that the DBT PE Protocol led to exacerbations of intentional self-injury urges or behaviors, PTSD, treatment dropout, or crisis service use. Overall, the results indicate that this integrated BPD and PTSD treatment is feasible to implement within one year of treatment, highly acceptable to patients and therapists, safe to administer, and shows promise as an effective intervention for PTSD in this complex and high-risk patient population. PMID:22503959

  18. Mechanisms of Change in Cognitive Processing Therapy and Prolonged Exposure Therapy for PTSD: Preliminary Evidence for the Differential Effects of Hopelessness and Habituation

    PubMed Central

    Resick, Patricia A.

    2013-01-01

    The present study examined two potential mechanisms of change, hopelessness cognitions and habituation, in a randomized controlled trial of cognitive processing therapy (CPT) and prolonged exposure therapy (PE) for posttraumatic stress disorder (PTSD). Participants were 171 adult women with a current primary diagnosis of sexual assault related PTSD. The potential mechanisms were examined by evaluating the intraindividual change in hopelessness within the course of both treatments and subjective units distress (SUDS) ratings (a proxy for habituation) within the course of PE. The effects of intraindividual change in the proposed mechanisms were then examined on within-treatment changes in PTSD symptoms. Findings indicated that the participants assigned to the CPT treatment had significantly greater pre-post reductions in hopelessness than those assigned to PE and that the changes in hopelessness predicted changes in PTSD symptoms (R2 = .24). Intraindividual changes in SUDS ratings for participants in the PE treatment condition also predicted changes in PTSD symptoms and did so independently of the effect of changes in hopelessness. Future research should examine these mechanisms using more intensive methods of data collection that would permit the demonstration of temporality of change. PMID:24363472

  19. The Induction of Tumor Necrosis Factor-alpha , Supeoxide Anion, Myeloperoxidase, and Superoxide Dismutase in the Peritoneal Lavage Cells of Mice after Prolonged Exposure to Dichloroacetate and Trichloroacetate

    PubMed Central

    Spildener, Jessica; Cearfoss, Jacquelyn

    2010-01-01

    The induction of phagocytic activation in response to prolonged treatment with different doses of dichloroacetate (DCA) and trichloroacetate (TCA) has been investigated in mice. Groups of B6C3F1 male mice were administered 7.7, 77, 154 and 410 mg of DCA or TCA/ kg/day , post orally, for 4- and 13-weeks. Peritoneal lavage cells (PLCs) were isolated and assayed for the different biomarkers of phagocytyic activation, including superoxide anion (SA), tumor necrosis factor-alpha (TNF-α), and myeloperoxidase (MPO). In addition, the role of superoxide dismutase (SOD) in the SA production was also assessed. DCA and TCA produced significant and dose-dependent increases in SA and TNF-α production and in MPO activity but the increases in response to the high doses of the compounds (> 77 mg/kg/day) in the 13-week treatment period were less significant than those produced in the 4-week treatment period. Also, dose-dependent increases in SOD activity were observed in both periods of treatments. In general, the results demonstrate significant induction of the biomarkers of phagocytic activation by doses of DCA and TCA that were previously shown to be non carcinogenic, with significantly greater increases observed at the earlier period of exposure, as compared with later period. These findings may argue against the contribution of those mechanisms to the hepatotoxicity/hepatocarcinogenicity of the compounds and suggest them to be early adaptive/ protective mechanisms against their long term effects. PMID:20391627

  20. Pdgfrβ+ Mural Preadipocytes Contribute to Adipocyte Hyperplasia Induced by High-Fat-Diet Feeding and Prolonged Cold Exposure in Adult Mice.

    PubMed

    Vishvanath, Lavanya; MacPherson, Karen A; Hepler, Chelsea; Wang, Qiong A; Shao, Mengle; Spurgin, Stephen B; Wang, Margaret Y; Kusminski, Christine M; Morley, Thomas S; Gupta, Rana K

    2016-02-01

    The expansion of white adipose tissue (WAT) in obesity involves de novo differentiation of new adipocytes; however, the cellular origin of these cells remains unclear. Here, we utilize Zfp423(GFP) reporter mice to characterize adipose mural (Pdgfrβ(+)) cells with varying levels of the preadipocyte commitment factor Zfp423. We find that adipose tissue contains distinct mural populations, with levels of Zfp423 distinguishing adipogenic from inflammatory-like mural cells. Using our "MuralChaser" lineage tracking system, we uncover adipose perivascular cells as developmental precursors of adipocytes formed in obesity, with adipogenesis and precursor abundance regulated in a depot-dependent manner. Interestingly, Pdgfrβ(+) cells do not significantly contribute to the initial cold-induced recruitment of beige adipocytes in WAT; it is only after prolonged cold exposure that these cells differentiate into beige adipocytes. These results provide genetic evidence for a mural cell origin of white adipocytes in obesity and suggest that beige adipogenesis may originate from multiple sources.

  1. Syntaxin 5 Overexpression and β-Amyloid 1-42 Accumulation in Endoplasmic Reticulum of Hippocampal Cells in Rat Brain Induced by Ozone Exposure.

    PubMed

    Hernández-Zimbrón, Luis Fernando; Rivas-Arancibia, Selva

    2016-01-01

    Oxidative stress is a risk factor for Alzheimer's disease and it is currently accepted that oxidative damage precedes the overproduction of A42 peptide. We have reported that ozone causes oxidative stress inducing neurodegeneration in the brain of rats. It is associated with A42 overproduction and intracellular accumulation in hippocampus. Organelles like mitochondria, intracellular membranes, and endoplasmic reticulum have been identified as sites of A42 production and accumulation affecting cellular metabolism. However whether ozone exposure induces overproduction and/or accumulation of A42 in endoplasmic reticulum has not been studied. We evaluated this effect in the endoplasmic reticulum of hippocampal cells of rats exposed chronically to low doses of ozone (0.25 ppm) at 7, 15, 30, 60, and 90 days. The effect of the presence of A42 in endoplasmic reticulum was analyzed evaluating the expression of the chaperone Syntaxin 5. Our results show an accumulation of A42 peptide in this organelle. It was observed by immunofluorescence and by WB in endoplasmic fractions from hippocampal cells of rats at 60 and 90 days of treatment. Significant overexpression of the chaperone Syntaxin 5 at 60 and 90 days of treatment was observed ((⁎) P < 0.05). These results indicate that the exposure to environmental pollutants could be involved as a risk factor for neurodegenerative processes. PMID:27366738

  2. Syntaxin 5 Overexpression and β-Amyloid 1–42 Accumulation in Endoplasmic Reticulum of Hippocampal Cells in Rat Brain Induced by Ozone Exposure

    PubMed Central

    Hernández-Zimbrón, Luis Fernando

    2016-01-01

    Oxidative stress is a risk factor for Alzheimer's disease and it is currently accepted that oxidative damage precedes the overproduction of A42 peptide. We have reported that ozone causes oxidative stress inducing neurodegeneration in the brain of rats. It is associated with A42 overproduction and intracellular accumulation in hippocampus. Organelles like mitochondria, intracellular membranes, and endoplasmic reticulum have been identified as sites of A42 production and accumulation affecting cellular metabolism. However whether ozone exposure induces overproduction and/or accumulation of A42 in endoplasmic reticulum has not been studied. We evaluated this effect in the endoplasmic reticulum of hippocampal cells of rats exposed chronically to low doses of ozone (0.25 ppm) at 7, 15, 30, 60, and 90 days. The effect of the presence of A42 in endoplasmic reticulum was analyzed evaluating the expression of the chaperone Syntaxin 5. Our results show an accumulation of A42 peptide in this organelle. It was observed by immunofluorescence and by WB in endoplasmic fractions from hippocampal cells of rats at 60 and 90 days of treatment. Significant overexpression of the chaperone Syntaxin 5 at 60 and 90 days of treatment was observed (⁎P < 0.05). These results indicate that the exposure to environmental pollutants could be involved as a risk factor for neurodegenerative processes. PMID:27366738

  3. Prolonged Exposure of Primary Human Muscle Cells to Plasma Fatty Acids Associated with Obese Phenotype Induces Persistent Suppression of Muscle Mitochondrial ATP Synthase β Subunit.

    PubMed

    Tran, Lee; Hanavan, Paul D; Campbell, Latoya E; De Filippis, Elena; Lake, Douglas F; Coletta, Dawn K; Roust, Lori R; Mandarino, Lawrence J; Carroll, Chad C; Katsanos, Christos S

    2016-01-01

    Our previous studies show reduced abundance of the β-subunit of mitochondrial H+-ATP synthase (β-F1-ATPase) in skeletal muscle of obese individuals. The β-F1-ATPase forms the catalytic core of the ATP synthase, and it is critical for ATP production in muscle. The mechanism(s) impairing β-F1-ATPase metabolism in obesity, however, are not completely understood. First, we studied total muscle protein synthesis and the translation efficiency of β-F1-ATPase in obese (BMI, 36±1 kg/m2) and lean (BMI, 22±1 kg/m2) subjects. Both total protein synthesis (0.044±0.006 vs 0.066±0.006%·h-1) and translation efficiency of β-F1-ATPase (0.0031±0.0007 vs 0.0073±0.0004) were lower in muscle from the obese subjects when compared to the lean controls (P<0.05). We then evaluated these same responses in a primary cell culture model, and tested the specific hypothesis that circulating non-esterified fatty acids (NEFA) in obesity play a role in the responses observed in humans. The findings on total protein synthesis and translation efficiency of β-F1-ATPase in primary myotubes cultured from a lean subject, and after exposure to NEFA extracted from serum of an obese subject, were similar to those obtained in humans. Among candidate microRNAs (i.e., non-coding RNAs regulating gene expression), we identified miR-127-5p in preventing the production of β-F1-ATPase. Muscle expression of miR-127-5p negatively correlated with β-F1-ATPase protein translation efficiency in humans (r = - 0.6744; P<0.01), and could be modeled in vitro by prolonged exposure of primary myotubes derived from the lean subject to NEFA extracted from the obese subject. On the other hand, locked nucleic acid inhibitor synthesized to target miR-127-5p significantly increased β-F1-ATPase translation efficiency in myotubes (0.6±0.1 vs 1.3±0.3, in control vs exposure to 50 nM inhibitor; P<0.05). Our experiments implicate circulating NEFA in obesity in suppressing muscle protein metabolism, and establish

  4. Prolonged Exposure of Primary Human Muscle Cells to Plasma Fatty Acids Associated with Obese Phenotype Induces Persistent Suppression of Muscle Mitochondrial ATP Synthase β Subunit

    PubMed Central

    Tran, Lee; Hanavan, Paul D.; Campbell, Latoya E.; De Filippis, Elena; Lake, Douglas F.; Coletta, Dawn K.; Roust, Lori R.; Mandarino, Lawrence J.; Carroll, Chad C.; Katsanos, Christos S.

    2016-01-01

    Our previous studies show reduced abundance of the β-subunit of mitochondrial H+-ATP synthase (β-F1-ATPase) in skeletal muscle of obese individuals. The β-F1-ATPase forms the catalytic core of the ATP synthase, and it is critical for ATP production in muscle. The mechanism(s) impairing β-F1-ATPase metabolism in obesity, however, are not completely understood. First, we studied total muscle protein synthesis and the translation efficiency of β-F1-ATPase in obese (BMI, 36±1 kg/m2) and lean (BMI, 22±1 kg/m2) subjects. Both total protein synthesis (0.044±0.006 vs 0.066±0.006%·h-1) and translation efficiency of β-F1-ATPase (0.0031±0.0007 vs 0.0073±0.0004) were lower in muscle from the obese subjects when compared to the lean controls (P<0.05). We then evaluated these same responses in a primary cell culture model, and tested the specific hypothesis that circulating non-esterified fatty acids (NEFA) in obesity play a role in the responses observed in humans. The findings on total protein synthesis and translation efficiency of β-F1-ATPase in primary myotubes cultured from a lean subject, and after exposure to NEFA extracted from serum of an obese subject, were similar to those obtained in humans. Among candidate microRNAs (i.e., non-coding RNAs regulating gene expression), we identified miR-127-5p in preventing the production of β-F1-ATPase. Muscle expression of miR-127-5p negatively correlated with β-F1-ATPase protein translation efficiency in humans (r = – 0.6744; P<0.01), and could be modeled in vitro by prolonged exposure of primary myotubes derived from the lean subject to NEFA extracted from the obese subject. On the other hand, locked nucleic acid inhibitor synthesized to target miR-127-5p significantly increased β-F1-ATPase translation efficiency in myotubes (0.6±0.1 vs 1.3±0.3, in control vs exposure to 50 nM inhibitor; P<0.05). Our experiments implicate circulating NEFA in obesity in suppressing muscle protein metabolism, and establish

  5. Effect of ozone exposure in vivo on response of bronchial rings in vitro: Role of intracellular Ca2+

    SciTech Connect

    Montano, L.M.; Jones, G.L.; O'Byrne, P.M.; Daniel, E.E. )

    1993-09-01

    In this study we investigated the role of intracellular Ca2+ in ozone- (O3) induced airway hyperresponsiveness. Acetylcholine-induced airway responses were measured before and after inhalation of O3 (3 ppm, 30 min) or dry air. In vitro experiments were performed with intact ring segments of third- to fifth-order bronchi. Bronchial responses to carbachol (CCh) were evaluated in Krebs solution (2.5 mM Ca2+) and in Ca(2+)-free [0.1 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA)] Krebs solution with or without indomethacin (IDM, 10(-5) M) and were expressed as percentage of the maximal KCl response (60 mM). Inhalation of O3, but not dry air, caused airway hyperresponsiveness to acetylcholine in vivo. Responses to 50% effective concentrations of CCh were similar in bronchial preparations from O3 and control animals (with or without IDM) in normal Krebs solution. In Ca(2+)-free solution, CCh induced a sustained (20-min) bronchial contraction. These contractions relaxed immediately when nifedipine or a high EGTA concentration was added to the organ bath. The sustained contraction was abolished when the tissues had been incubated with cyclopiazonic acid (10(-5) M), a novel inhibitor of the sarcoplasmic reticulum Ca2+ pump. After O3 exposure, responses of the bronchial smooth muscle (in Ca(2+)-free medium without IDM) were increased (P < 0.05) compared with controls during the first and second CCh stimulations. This O3-induced increase in response to CCh in Ca(2+)-free solution was abolished when the tissues were incubated with IDM.

  6. Physiological and morphological responses of olive plants to ozone exposure during a growing season.

    PubMed

    Minnocci, Antonio; Panicucci, Alberto; Sebastiani, Luca; Lorenzini, Giacomo; Vitagliano, Claudio

    1999-05-01

    We studied physiological (gas exchange and stomatal aperture) and morphological (individual leaf area and stomatal density) responses in leaves of five-year-old olive plants (Olea europaea L. cvs. Frantoio and Moraiolo) exposed to filtered air containing < 3 ppb O(3) or 100 ppb O(3) for 5 h day(-1) for 120 days in fumigation chambers. After 100 days of treatment, leaf drop and development of necrotic spots were observed in O(3)-fumigated plants of Moraiolo but not of Frantoio. Significant reductions in photosynthetic activity (57%) and stomatal conductance (69%) were detected in O(3)-fumigated plants of Frantoio compared with control plants. In O(3)-fumigated plants of Moraiolo, the decrease in photosynthetic activity (17%) was not statistically significant, but a significant reduction in stomatal conductance (40%) was observed. In both cultivars, leaves that developed after exposure to O(3) showed decreased stomatal aperture (63.6 and 54.8% with respect to the Frantoio and Moraiolo controls, respectively) and one-sided leaf area, and increased stomatal density compared with control leaves. Actual transpiring stomatal surface decreased substantially in both Frantoio (59.8%) and Moraiolo (56.3%) in response to O(3) treatment. Relative transpiring stomatal surface (RTSS) in Frantoio decreased from 0.54 (control) to 0.27% (O(3) treated) of total leaf surface. The corresponding values for Moraiolo were 0.79 and 0.42%. However, because the RTSS of Moraiolo leaves in the O(3) treatment was 0.42 versus 0.27% in Frantoio, the potential uptake of O(3) was higher for Moraiolo plants than for Frantoio plants. The large O(3)-induced reduction in transpiring stomatal surface in both cultivars could have significant effects on olive productivity in the Mediterranean area, where high O(3) concentrations persist for long periods during the year. PMID:12651561

  7. Design considerations for ozone and acid-aerosol exposure and health investigations: the Fairview Lake Summer Camp - photochemical smog case study

    SciTech Connect

    Lioy, P.J.; Spektor, D.; Thurston, G.; Citak, K.; Lippmann, M.

    1987-01-01

    The health effects associated with ozone and acidic particulate sulfate exposures to active children have been and are being addressed in field epidemiological studies at summer camps in rural areas of the Northeastern U.S. The rationale and study design for studies, which have been conducted in Pennsylvania and New Jersey, are developed and reviewed. As background, results are summarized for human clinical and epidemiological studies and animal studies. These provided the basis for selection of health outcomes. Measured results from chemical characterization and transport studies are reviewed to define the criteria used for selection of a site affected by high ozone and acid species during photochemical smog episodes. The integration of the study design is discussed in detail by reviewing its application to the 1984 - Fairview Lake Camp Study (July 8 to August 4). The features of the camp study are reviewed, including the study population, pulmonary function procedures and analyses, air pollution monitoring instrumentation, and the site characteristics.

  8. Is it true that ozone is always toxic? The end of a dogma

    SciTech Connect

    Bocci, Velio . E-mail: bocci@unisi.it

    2006-11-01

    There are a number of good experimental studies showing that exposure by inhalation to prolonged tropospheric ozone damages the respiratory system and extrapulmonary organs. The skin, if extensively exposed, may also contribute to the damage. The undoubtful strong reactivity of ozone has contributed to establish the dogma that ozone is always toxic and its medical application must be proscribed. Although it is less known, judiciously practiced ozonetherapy is becoming very useful either on its own or applied in combination with orthodox medicine in a broad range of pathologies. The opponents of ozonetherapy base their judgment on the ozone chemistry, and physicians, without any knowledge of the problem, are often skeptical. During the last 15 years, a clear understanding of the action of ozone in biology and medicine has been gained, allowing today to argue if it is true that ozone is always toxic. The fundamental points that are discussed in this paper are: the topography, anatomical and biochemical characteristics of the organs daily exposed to ozone versus the potent antioxidant capacity of blood exposed to a small and precisely calculated dose of ozone only for a few minutes. It is becoming clear how the respiratory system undergoing a chronic oxidative stress can release slowly, but steadily, a huge amount of toxic compounds able to enter the circulation and cause serious damage. The aim of this paper is to objectively evaluate this controversial issue.

  9. Adaptation of visually evoked responses of relay cells in the dorsal lateral geniculate nucleus of the cat following prolonged exposure to drifting gratings.

    PubMed

    Shou, T; Li, X; Zhou, Y; Hu, B

    1996-01-01

    Adaptation of visual cortical cells' responses is observed following repeated presentation of grating stimuli. Grating adaptation is believed to exist only at the cortical level. The purpose of this study was to see if grating adaptation also occurs in the lateral geniculate nucleus. We studied the responses of 164 relay cells in layer A and A1 of the dorsal lateral geniculate nucleus (LGNd) to grating stimuli. Normal cats, as well as cats in which visual cortex was ablated, were studied. Adaptation was investigated using repeated presentation of gratings of different contrasts and orientations. The results showed the following: (1) Grating adaptation reduced the responses of 46% of the LGNd cells recorded. The responses normally decreased within 30 s and then stabilized. However, there was heterogeneity in the effects observed. About 38% of the cells studied were not affected by the adapting gratings. Some cells (16%) showed facilitation rather than habituation of their responses to test stimuli. (2) There was no significant difference between X and Y cells in their susceptibility to adaptation. This suggests that grating adaptation is a general property, independent of cell type. (3) The contrast-response curves of 57% of the LGNd cells studied shifted down after exposure to high-contrast adapting gratings. (4) Adapting gratings of the cells' preferred orientation decreased the orientation sensitivity of 56% of the orientation-sensitive cells. Adapting gratings at the nonpreferred orientation did not affect orientation sensitivity. (5) Prolonged grating adaptation also reduced the responses of 49% of the LGNd cells after inactivation of cortical inputs to the LGNd. PMID:8870219

  10. Ozone exposure, vitamin C intake, and genetic susceptibility of asthmatic children in Mexico City: a cohort study

    PubMed Central

    2013-01-01

    Background We previously reported that asthmatic children with GSTM1 null genotype may be more susceptible to the acute effect of ozone on the small airways and might benefit from antioxidant supplementation. This study aims to assess the acute effect of ozone on lung function (FEF25-75) in asthmatic children according to dietary intake of vitamin C and the number of putative risk alleles in three antioxidant genes: GSTM1, GSTP1 (rs1695), and NQO1 (rs1800566). Methods 257 asthmatic children from two cohort studies conducted in Mexico City were included. Stratified linear mixed models with random intercepts and random slopes on ozone were used. Potential confounding by ethnicity was assessed. Analyses were conducted under single gene and genotype score approaches. Results The change in FEF25-75 per interquartile range (60 ppb) of ozone in persistent asthmatic children with low vitamin C intake and GSTM1 null was −91.2 ml/s (p = 0.06). Persistent asthmatic children with 4 to 6 risk alleles and low vitamin C intake showed an average decrement in FEF25-75 of 97.2 ml/s per 60 ppb of ozone (p = 0.03). In contrast in children with 1 to 3 risk alleles, acute effects of ozone on FEF25-75 did not differ by vitamin C intake. Conclusions Our results provide further evidence that asthmatic children predicted to have compromised antioxidant defense by virtue of genetic susceptibility combined with deficient antioxidant intake may be at increased risk of adverse effects of ozone on pulmonary function. PMID:23379631

  11. Ca2+ Transport in Membrane Vesicles from Pinto Bean Leaves and Its Alteration after Ozone Exposure 1

    PubMed Central

    Castillo, Federico J.; Heath, Robert L.

    1990-01-01

    The influence of ozone on Ca2+ transport in plant membranes from pinto bean (Phaseolus vulgaris L. var Pinto) leaves was investigated in vitro by means of a filtration method using purified vesicles. Two transport mechanisms located at the plasma membrane are involved in a response to ozone: (a) passive Ca2+ influx into the cell and (b) active Ca2+ efflux driven by an ATP-dependent system, which has two components: a primary Ca2+ transport directly linked to ATP which is partially activated by calmodulin and a H+/Ca2+ antiport coupled to activity of a H+-ATPase. The passive Ca2+ permeability is increased by ozone. A triangular pulse of ozone stimulates a higher influx of Ca2+ than does a square wave, even though the total dose was the same (0.6 microliter per liter × hour). Leaves exposed to a square wave did not exhibit visible injury and were still able to recover from oxidant stress by activation of calmodulin-dependent Ca2+ extrusion mechanisms. On the other hand, leaves exposed to a triangular wave of ozone, exhibit visible injury and lost the ability of extruding Ca2+ out of the cell. PMID:16667780

  12. Differences in pulmonary biochemical and inflammatory responses of rats and guinea pigs resulting from daytime or nighttime, single and repeated exposure to ozone

    SciTech Connect

    Van Bree, L.; Marra, M.; Rombout, P.J. )

    1992-10-01

    Rats and guinea pigs were exposed to 0.8 mg ozone (O3)/m3 (approximately 0.4 ppm) for 12 hr during the daytime, 12 hr during the nighttime, or continuously to investigate circadian variation in O3-induced pulmonary toxicity during single and repeated O3 exposures. Biomarkers in bronchoalveolar lavage (BAL) fluid and lung tissues were measured as indicators of biochemical and inflammatory responses. Nighttime O3 exposure of rats resulted in larger increases of protein, albumin, and inflammatory cells in BAL fluid compared to those after daytime O3 exposure and this daytime-nighttime difference was statistically significant (p < 0.05). Single daytime or nighttime O3 exposure of guinea pigs resulted in comparable increases of BAL fluid proteins and inflammatory cells without a daytime-nighttime difference. Nighttime and continuous O3 exposure of rats for 3 days resulted in comparable increases in lung antioxidant enzyme activities, both of which differed statistically from effects from daytime O3 exposures (p < 0.05). Continuous O3 exposure of guinea pigs for 3 days caused, in general, statistically larger increases in lung tissue parameters compared to nighttime O3 exposures (p < 0.05). These results suggest that the extent of O3-induced acute pulmonary biochemical and inflammatory responses is directly related to the level of physical and respiratory activity. For rats, effects from continuous O3 exposure appear to be controlled by the nighttime, physically active period. In guinea pigs, the comparable responses following daytime or nighttime O3 exposure seem in accordance with their random behavioral daily activity pattern. This study supports the view that physical activity-related increases in inhaled dose significantly enhance the pulmonary O3 responses.

  13. Enhanced phagocytosis by alveolar macrophages induced by short-term ozone insult

    SciTech Connect

    Christman, C.A.; Schwartz, L.W.

    1982-08-01

    In vitro phagocytosis of inert microspheres by the alveolar macrophage (AM) was evaluated after in vivo exposure to 0.8 ppm ozone for 3, 7, or 20 days. AM were collected by bronchoalveolar lavage from rats, allowed to adhere to glass, and incubated with carbon-coated latex microspheres. The percentages of phagocytic cells were determined by light microscopy after 0.25, 0.5, 1, 2, 4, 8, and 24 hr of incubation. Morphological features of AM were evaluated by scanning electron microscopy (SEM) and an index of cell spreading was determined by image analysis of SEM photomicrographs. An enhanced phagocytic activity was observed after ozone exposure, with the greatest increase on Day 3. This enhanced phagocytic activity correlated with an increase in cell spreading. The results, which suggest that prolonged ozone insult produces an altered AM population, support previous morphological observations.

  14. Challenges and Successes in Dissemination of Evidence-Based Treatments for Posttraumatic Stress: Lessons Learned From Prolonged Exposure Therapy for PTSD.

    PubMed

    Foa, Edna B; Gillihan, Seth J; Bryant, Richard A

    2013-05-01

    Posttraumatic stress disorder (PTSD) poses monumental public health challenges because of its contribution to mental health, physical health, and both interpersonal and social problems. Recent military engagements in Iraq and Afghanistan and the multitude of resulting cases of PTSD have highlighted the public health significance of these conditions. There are now psychological treatments that can effectively treat most individuals with PTSD, including active duty military personnel, veterans, and civilians. We begin by reviewing the effectiveness of these treatments, with a focus on prolonged exposure (PE), a cognitive-behavioral therapy (CBT) for PTSD. Many studies conducted in independent research labs have demonstrated that PE is highly efficacious in treating PTSD across a wide range of trauma types, survivor characteristics, and cultures. Furthermore, therapists without prior CBT experience can readily learn and implement the treatment successfully. Despite the existence of highly effective treatments like PE, the majority of individuals with PTSD receive treatments of unknown efficacy. Thus, it is crucial to identify the barriers and challenges that must be addressed in order to promote the widespread dissemination of effective treatments for PTSD. In this review, we first discuss some of the major challenges, such as a professional culture that often is antagonistic to evidence-based treatments (EBTs), a lack of clinician training in EBTs, limited effectiveness of commonly used dissemination techniques, and the significant cost associated with effective dissemination models. Next, we review local, national, and international efforts to disseminate PE and similar treatments and illustrate the challenges and successes involved in promoting the adoption of EBTs in mental health systems. We then consider ways in which the barriers discussed earlier can be overcome, as well as the difficulties involved in effecting sustained organizational change in mental health

  15. Subclinical and Overt Adverse Cardiac Effects with Ozone Inhalation in Rats: Potentially Dire Implications of Low Exposures

    EPA Science Inventory

    Ozone is a ubiquitous smog-associated photochemical oxidant with deleterious health effects. While most of the adverse effects described to date involve the respiratory system (i.e, decrements in lung function, airway injury and inflammation, exacerbation of asthma, and compromis...

  16. Age-related differences in pulmonary effects of acute and subchronic episodic ozone exposures in Brown Norway rats

    EPA Science Inventory

    Ozone (O3) is known to induce adverse pulmonary and systemic health effects. Importantly, children and older persons are considered at-risk populations for O3-induced dysfunction, yet the mechanisms accounting for the age-related pulmonary responses to O3 are uncertain. In this s...

  17. Ozone concentration and pulmonary response relationships for 6. 6-hour exposures with five hours of moderate exercise to 0. 08, 0. 10, and 0. 12 ppm

    SciTech Connect

    Horstman, D.H.; Folinsbee, L.J.; Ives, P.J.; Abdul-Salaam, S.; McDonnell, W.F. )

    1990-11-01

    The magnitudes of pulmonary responses we previously observed (1) following 6.6-h exposures to 0.12 ppm ozone (O3) suggested that responses would also occur with similar exposures at lower O3 concentrations. The objective of this study was to determine the extent of pulmonary function decrements, respiratory discomfort, and increased airway reactivity to methacholine induced by exposure to O3 below 0.12 ppm. Separate 6.6-h chamber exposures to 0.00, 0.08, 0.10, and 0.12 ppm O3 included six 50-min periods of moderate exercise (VE approximately equal to 39 L/min, HR approximately equal to 115 bpm, and VO2 approximately equal to 1.5 L/min). Each exercise period was followed by 10 min of rest. A 35-min lunch break was included midway through the exposure. Although not intended as an exact simulation, the overall duration, intensity, and metabolic requirements of the exercise performed were representative of a day of moderate to heavy work or play. Preexposure FEV1 averaged 4.39 L, and essentially no change (+0.03 L) occurred with exposure to 0.00 ppm O3. Significant decreases (p less than 0.01) of -0.31, -0.30, and -0.54 L were observed with exposures to 0.08, 0.10, and 0.12 ppm, respectively. The provocative dose of methacholine required to increase airway resistance by 100% (PD100) was 58 cumulative inhalation units (CIU) following exposure to 0.00 ppm and was significantly reduced (p less than 0.01) to 37 CIU at 0.08, 31 CIU at 0.10, and 26 CIU at 0.12 ppm O3; reductions in PD100 are considered indicative of increases in nonspecific airway responsiveness.

  18. Ozone-concentration and pulmonary-response relationships for 6. 6-hour exposures with five hours of moderate exercise to 0. 08, 0. 10, and 0. 12 ppm

    SciTech Connect

    Horstman, D.H.; Folinsbee, L.J.; Ives, P.J.; Salaam, S.A.; McDonnell, W.F.

    1990-01-01

    The magnitudes of pulmonary responses the authors previously observed (1) following 6.6-h exposure to 0.12 ppm ozone (O{sub 3}) suggested that responses would also occur with similar exposures at lower O{sub 3} concentrations. The objective of the study was to determine the extent of pulmonary function decrements, respiratory discomfort, and increased airway reactivity to methacholine induced by exposure to O{sub 3} below 0.12 ppm. Separate 6.6-h chamber exposures to 0.00, 0.08, 0.10, and 0.12 ppm O3 included six 50-min periods of moderate exercise (VE = 39 L/min, HR = 115 bpm, and VO2 = 1.5 L/min). Each exercise period was followed by 10 min of rest. A 35-min lunch break was included midway through the exposure. Although not intended as an exact simulation, the overall duration, intensity, and metabolic requirements of the exercise performed were representative of a day of moderate to heavy work or play. Preexposure FEV, averaged 4.39 L, and essentially no change (+0.03 L) occurred with exposure to 0.00 ppm O{sub 3}. Significant decreases (p<0.01) of -0.31, -0.30, and -0.54 L were observed with exposures to 0.08, 0.10, and 0.12 ppm, respectively. The study concludes that exposure to O{sub 3} at levels often found in ambient air while engaged in activity representative of a typical day of moderate to heavy work or play induced clinically meaningful pulmonary responses.

  19. Ozone Risk Assessment Utilities

    1999-08-10

    ORAMUS is a user-friendly, menu-driven software system that calculates and displays user-selected risk estimates for health effects attributable to short-term exposure to tropospheric ozone. Inputs to the risk assessment are estimates of exposure to ozone and exposure-response relationships to produce overall risk estimates in the form of probability distributions. Three fundamental models are included: headcount risk, benchmark risk, and hospital admissions. Exposure-response relationships are based on results of controlled human exposure studies. Exposure estimates aremore » based on the EPA''s probabilistic national ambient air quality standards (NAAQS) exposure model, pNEM/Osub3, which simulates air quality associated with atta